History of the Decline and Fall of the Roman Empire — Volume 5 — Edward Gibbon¶
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Executive summary¶
Volume 5 of Gibbon's Decline and Fall covers roughly the eighth through eleventh centuries, tracing the transformation of the Roman world through religious controversy, barbarian conquest, and the rise of new powers. Gibbon's central thesis is that the Western Empire did not simply collapse but underwent a long, complex metamorphosis driven by three forces: the iconoclast controversy, the rise of Islam, and the emergence of new political actors (Franks, Normans, Turks). His method combines sweeping geographic coverage with attention to institutional detail, treating religious movements as historical forces with political and military consequences. The volume moves from the iconoclast crisis and papal independence (Chapter XLIX), through the rise and expansion of Islam (Chapters L–LII), to the state of the Eastern Empire (Chapter LIII), then to the Paulicians (LIV), the barbarian peoples of the north (LV), the Normans in Italy (LVI), the Seljuk Turks (LVII), and finally the First Crusade (LVIII). Gibbon is openly skeptical of religious claims, treats the papacy's temporal power as founded on rebellion and forgery, and presents the Crusades as a manufactured movement driven by papal ambition and popular fanaticism.
The central thesis¶
Gibbon's overarching argument is that the Roman Empire's decline was not a single catastrophic event but a long process of transformation driven by three interlocking forces: religious controversy (especially iconoclasm), the rise of Islam, and the emergence of new political actors. He makes a bold causal claim in Chapter XLIX: "a question of popular superstition produced the revolt of Italy, the temporal power of the popes, and the restoration of the Roman empire in the West." Religious practice, not doctrine, drives political transformation. Gibbon treats church history only insofar as it "materially affected" the empire's decline, leaving speculative theology to divines. The volume's arc shows the Eastern Empire's gradual contraction, the papacy's rise through rebellion and forgery, Islam's explosive expansion and subsequent fragmentation, and the eventual emergence of new powers (Normans, Turks) that set the stage for the Crusades.
Argument map¶
Chapter XLIX — The iconoclast controversy as the hinge between religious and political history: image worship's development, Leo III's edicts, papal rebellion, the Frankish alliance, the Donation of Constantine as forgery, Charlemagne's coronation, and the decay of the imperial title.
Chapters L–LII — The rise of Islam: Arabia's geography and inhabitants, Muhammad's life and doctrine, the Koran's composition, the early conquests (Persia, Syria, Egypt, Africa, Spain), the two sieges of Constantinople, Greek fire, the Abbasid revolution, and the caliphate's cultural achievements and decline.
Chapter LIII — The Eastern Empire's fate: its wealth, palace, titles, military tactics, and the loss of the Latin tongue; Byzantine learning as derivative and sterile.
Chapter LIV — The Paulicians: a dualist sect persecuted by Byzantine emperors, transplanted to Thrace, and presented as "seeds of the Reformation."
Chapter LV — The Bulgarians, Hungarians, and Russians: origins, migrations, inroads, and conversion.
Chapter LVI — The Normans in Italy: Robert Guiscard's rise, the conquest of Sicily, wars with Byzantium, and the Norman kingdom's fall.
Chapter LVII — The Seljuk Turks: their rise, the Battle of Manzikert, the conquest of Anatolia, and the oppression of Jerusalem.
Chapter LVIII — The First Crusade: origins, numbers, leaders, the march to Constantinople, the sieges of Nice, Antioch, and Jerusalem, and the Latin kingdom's institutions.
Core concepts and frameworks¶
Religious practice as historical force. Gibbon treats theological disputes (iconoclasm, Islam, Paulicianism) primarily as political and military phenomena with material consequences, not as matters of truth or falsehood.
The "weakness of enemies" thesis. Arab conquests succeeded less through military superiority than through the degeneration of neighboring empires—Persian demoralization, Byzantine religious factionalism, and internal collapse.
The "emulation theory" of cultural achievement. Gibbon argues that "the emulation of states and individuals is the most powerful spring of the efforts and improvements of mankind." The Byzantine Empire's isolation from competitors and judges explains its cultural sterility.
The "invincible in opinion" principle. The Saracens were "invincible in fact, since they were invincible in opinion"—psychological factors (martyrdom-seeking, fatalism) mattered as much as material ones.
The penitential economy. Gibbon traces the crusade indulgence to medieval penitential codes, showing how commutation, flagellation, and military substitution created a system where sinners could atone by killing infidels.
The "monster with a hundred heads." Germany's dissolution into a federative anarchy under the imperial name, producing the Imperial Diet as an enduring institution.
The "secret reformation." Since Luther and Calvin, a quieter reformation has worked within reformed churches, moving toward rational theology and liberty of conscience.
Themes¶
The irony of religious zeal. Gibbon repeatedly shows that religious enthusiasm produces political consequences its practitioners neither intend nor foresee—the iconoclast controversy creates papal power; the crusade indulgence channels violence into holy war.
The fraudulence of institutional foundations. The Donation of Constantine, the forged letter of St. Peter, the Holy Lance, and the Easter miracle of the holy fire are all exposed as pious frauds that nonetheless shaped history.
The transformation of conquerors. Arabs become heirs of imperial civilization; Normans become Mediterranean princes; Turks adopt Persian culture. Conquest changes the conquerors as much as the conquered.
The structural weakness of despotism. Provincial governors inevitably aspire to independence; mercenary guards become praetorians; ceremonial hierarchy substitutes for functional governance.
The contrast between Eastern and Western Christianity. Byzantine Christianity teaches "to suffer and to yield"; Latin Christianity, despite its superstitions, preserves a "free and generous spirit" that eventually produces the Reformation.
The decline of martial virtue. Luxury "relaxed the nerves" of the Abbasid caliphate; Byzantine reliance on mercenaries signals decay; the Normans succeed where effeminate Greeks fail.
The contingency of history. Gibbon's counterfactual—"Perhaps the interpretation of the Koran would now be taught in the schools of Oxford"—underscores his sense that history's course was not inevitable.
Detailed chapter or part walk-through¶
Chapter XLIX: The Iconoclast Controversy and the Birth of Papal Power¶
Gibbon opens with his boldest causal claim: the iconoclast controversy—the dispute over religious images in the eighth and ninth centuries—was not merely theological but a pivotal historical force. He asserts that "a question of popular superstition produced the revolt of Italy, the temporal power of the popes, and the restoration of the Roman empire in the West." He states his methodological principle explicitly: he treats church history only insofar as it "materially affected" the empire's decline, leaving speculative theology to divines.
The development of image worship. Gibbon traces image veneration from primitive Christian aversion to established practice. Early Christians inherited the Mosaic prohibition on representations of the Deity. The first censure of images appears at the Council of Illiberis (c. 300 CE). Under Constantine's successors, bishops "condescended to indulge a visible superstition, for the benefit of the multitude"—a cynical pastoral management. Veneration of the cross and relics preceded images, and pagan practices (genuflection, incense, candles) "again" stole into the church. A geographic divide emerged: the "warm imagination of the Greeks and Asiatics" embraced images, while the "rude Barbarians and Arian clergy of the West" remained colder.
A critical weakness was that no one knew what Christ, Mary, or the apostles looked like. This gap produced the acheiropoieta—images "not made by hands." Gibbon dissects the Edessa legend: Eusebius recorded correspondence between Christ and King Abgarus but "most strangely forgets the picture." The image supposedly emerged after 500 years of concealment and saved Edessa from Chosroes Nushirvan. Gibbon dates the fable's invention to between 521 and 594 CE, most probably after the siege of Edessa in 540. He notes the irony that St. Luke, "perhaps a physician," was "forced to exercise the occupation of a painter, so profane and odious in the eyes of the primitive Christians."
The iconoclast controversy. The chief external pressure for reform came from Jews and Muslims, whose monotheistic rejection of images carried weight because Muslim victories over Christian cities—cities fortified with icons and promised miraculous defense—seemed to prove divine judgment. The fall of Edessa and the loss of its famous image is cited as evidence.
Leo the Isaurian, an illiterate "martial peasant," hated images due to his education, reason, and contact with Jews and Arabs. Gibbon emphasizes his hypocrisy: for ten years Leo bowed before idols he despised while professing orthodoxy to the pope. His first edict was moderate—raising images beyond reach—but resistance provoked total proscription. The movement was sustained by "the zeal and despotism of six emperors" over 120 years.
The council summoned by Constantine V in 754 showed "many symptoms of reason and piety," despite being stigmatized by "triumphant bigotry." The 338 bishops unanimously condemned image-worship as "a corruption of Christianity and a renewal of Paganism." However, Gibbon suspects most bishops "sacrificed their secret conscience to the temptations of hope and fear." He contrasts this with the Reformation, where "freedom and knowledge had expanded all the faculties of man."
Resistance was violent: mobs attacked iconoclast officials, a naval rebellion was crushed by Greek fire, and the usurper Artavasdes restored images before being defeated. The monks are portrayed as conspirators, with John of Damascus as their chief literary champion. Gibbon is openly skeptical of monastic claims of martyrdom, admitting he cannot examine "how far the monks provoked, nor how much they have exaggerated, their real and pretended sufferings."
The papal rebellion. Gibbon argues that the popes, through popular election and imperial neglect, "insensibly imbibed the virtues and the ambition of a prince." He states plainly that "it is agreed, that in the eighth century, their dominion was founded on rebellion, and that the rebellion was produced, and justified, by the heresy of the Iconoclasts."
The evidence is sharply contested. Byzantine sources unanimously claim the popes pronounced separation from the East, deprived the emperor of revenue and sovereignty in Italy, and excommunicated him—and these Greek writers, being more attached to religion than country, actually praise the popes for this. Catholic champions celebrate this as a "great and glorious example of the deposition of royal heretics." Protestant polemicists use the same facts to condemn papal "insolence and treason." Moderate Gallican Catholics defend the popes' personal sanctity while disapproving of the alleged act.
Gibbon is skeptical of all partisans. He notes that the Greek sources "are apt to confound the times and actions of two Gregories"—a significant source-critical problem. The Liber Pontificalis is "barbarous" in style, "partial" in narrative, and full of "trifling" details, though it "must be read as a curious and authentic record of the times." His most pointed remark: "In the field of controversy I always pity the moderate party, who stand on the open middle ground exposed to the fire of both sides."
The birth of papal temporal power. Gibbon quotes extensively from two surviving letters of Pope Gregory II to Leo III, which he characterizes as exhibiting "the portrait, or at least the mask, of the founder of the papal monarchy." The letters are insulting—Gregory mocks Leo's ignorance—and theologically weak: Gregory falsely asserts the perpetual use of images and their presence in all six synods. Gregory claims the pope may "lawfully chastise the kings of the earth" through excommunication and threatens that the Lombards and Western barbarians are eager to avenge the Eastern persecution.
Following the edict, Italian cities rose in defense of images. Italians withheld tribute and destroyed statues of Leo. Imperial attempts to arrest the popes failed; Greek troops were massacred. At Ravenna, the exarch was killed in a sedition. Gregory convened a synod of 93 bishops that excommunicated all image-destroyers, implicitly including the emperor. Yet the popes then moderated: they prevented election of a rival emperor, urged Italians to remain nominally under Byzantine sovereignty, and allowed the exarch to reside in Ravenna as "a captive rather than a master."
Gibbon's most striking analytical passage concerns what Rome's "liberty" actually meant. Rome was "rescued, after seven hundred and fifty years of servitude"—but the Romans were "devoid of knowledge, or virtue, again to build the fabric of a commonwealth." The population was "the offspring of slaves and strangers," despised by barbarians. Gibbon quotes Bishop Liutprand: calling someone a "Roman" meant "whatever is base, whatever is cowardly, whatever is perfidious." The new republican forms were a "rough model" without the spirit; the result was "tumultuous conflict of vicentiousness and oppression." Religion supplied the want of laws; the pope became "first magistrate or prince of the city."
The Frankish rescue and the forged letter. The Lombard king Liutprand, at the Vatican gate, was moved by Pope Gregory II to withdraw, then deposited his weapons and crown on St. Peter's tomb. But Gibbon dismisses this as "the illusion, perhaps the artifice, of the moment." Liutprand invaded the Exarchate, and Ravenna—described as "impregnable"—fell to his successor Astolphus, ending the line of exarchs.
Pope Gregory III first appealed to Charles Martel, who was too busy to help. His son Pepin took up the cause. Pope Stephen III made a dramatic personal journey across the Alps, then returned "not as a suppliant, but as a conqueror" at the head of a Frankish army. Gibbon highlights an "extraordinary letter" written in the name of St. Peter himself, threatening eternal damnation if the Franks failed to defend Rome. Gibbon notes that enemies of the popes called this fraud and blasphemy, but adds dryly that the popes "surely meant to persuade rather than deceive."
After twenty years of Lombard decline, Charlemagne—allied with Pope Adrian I—besieged Pavia. Desiderius, the last Lombard king, surrendered. The Lombards then became "brethren, rather than subjects" of the Franks.
The fraudulent foundations of papal power. Gibbon describes the reciprocal exchange of legitimacy and territory between the papacy and the Carolingians. The Franks sought papal sanction to depose the last Merovingian king, Childeric. Pope Zachary declared that the nation might lawfully unite title and authority in one person. Childeric was degraded, shaved, and confined to a monastery. The royal unction borrowed from the kings of Israel transformed "a German chieftain" into "the Lord's anointed"—a rite Gibbon dismisses as sustained by "superstition and vanity."
The popes thundered an anathema against any future election outside the Carolingian race. After the loss of the Exarchate, the Romans conferred the patriciate on Charles Martel and his posterity. For twenty-six years between the Lombard conquest and his imperial coronation, Charlemagne ruled Rome as his own: the people swore allegiance, money was coined in his name, justice was administered, and papal elections were confirmed by his authority. Gibbon concludes that "except an original and self-inherent claim of sovereignty, there was not any prerogative remaining, which the title of emperor could add to the patrician of Rome."
Pepin's donation of the Exarchate transformed the church's ancient patrimony of farms into "the temporal dominion of cities and provinces." Gibbon condemns papal ambition and avarice, suggesting a Christian priest should have rejected an earthly kingdom. However, he defends the donation on legal grounds: the Greek emperor had forfeited his right, Pepin had lawfully conquered the territory, and "every one may accept, without injury, whatever his benefactor can bestow without injustice."
Gibbon describes the Donation of Constantine as a forgery produced by "some apostolic scribe, perhaps the notorious Isidore" before the end of the eighth century. The document claimed that Constantine, cured of leprosy and baptized by Pope Sylvester, resigned sovereignty over Rome, Italy, and the Western provinces to the popes. The forgery was "productive of the most beneficial effects" for the papacy: it convicted the Greek emperors of usurpation, freed popes from gratitude to the Carolingians, and made papal sovereignty independent of popular choice. Lorenzo Valla exposed it in the fifteenth century; by the next century, historians and even poets mocked it; popes themselves "indulged a smile at the credulity of the vulgar." Yet the "false and obsolete title still sanctifies their reign."
The coronation of Charlemagne. Gibbon argues that the popes "consummated the separation of Rome and Italy" by crowning Charlemagne emperor in 800 CE, driven less by theology than by political self-interest. The popes had tasted sovereignty during the schism; submission to Byzantium meant revenge from a jealous tyrant. Only reviving the Western empire could repay Charlemagne and secure papal rule.
On Christmas Day 800, Leo III placed a crown on Charlemagne's head, and the crowd acclaimed him "Augustus" and "emperor of the Romans." Gibbon dismisses Charlemagne's later claim of ignorance: "the preparations of the ceremony must have disclosed the secret."
Gibbon's critical assessment of Charlemagne. Gibbon explicitly resists the hagiographic tradition. Morally, chastity was not among Charlemagne's virtues—nine wives or concubines, many bastards, and daughters of "licentious manners." Gibbon lists his cruelties: the beheading of 4,500 Saxons, the treatment of his brother Carloman's sons, and the suppression of rebellion. His Saxon laws were "sanguinary." Gibbon deflates his military reputation: his activity was a "national, rather than a personal, virtue"—the Franks were naturally vagrant. He never faced an equal antagonist. His legislation was "not a system, but a series of occasional and minute edicts." His empire depended on one man's life; he divided kingdoms among sons; he empowered the clergy who later degraded his son Lewis.
The German emperors and the Italian cities. Gibbon argues that the German emperors' attempts to rule Italy were doomed by structural weakness: they lacked the resources, administrative machinery, and military discipline that true empire requires. The Italian city-republics, by contrast, developed a "martial spirit" and "invincible genius of liberty" that defeated even the ablest emperors. Meanwhile, the German monarchy itself dissolved into a "monster with a hundred heads"—a federative anarchy that nonetheless produced the enduring institution of the Imperial Diet.
Gibbon's rhetorical climax contrasts the hollow theatrical majesty of Emperor Charles IV with the real but concealed power of Augustus. Charles had no village of his own; his army crossing the Alps numbered only 300 horse. He was crowned in Milan's cathedral, but the city gates were shut against him; he was effectively a captive of the Visconti. Crowned again in the Vatican, he withdrew immediately without spending a night in Rome, per a secret treaty. His only real exercise of authority was selling privileges and titles. His son's election was secured with Italian gold; Charles himself was arrested by a butcher in Worms and held hostage in a public inn for his debts.
Chapter L: Description of Arabia and Its Inhabitants¶
Gibbon opens this chapter by announcing a major transition: after six hundred years of tracing the "fleeting Caesars of Constantinople and Germany," he now turns to the rise of Islam during the reign of Heraclius. His central claim is that Mahomet—"with the sword in one hand and the Koran in the other"—erected his throne "on the ruins of Christianity and of Rome."
Geography. Gibbon provides a detailed physical description of the Arabian peninsula, which he conceives as a triangle of "spacious but irregular dimensions." The peninsula is roughly four times the size of Germany or France, but mostly "stony and sandy." Unlike Tartary, which has vegetation, Arabia is a "dreary waste" of sand intersected by naked mountains, scorched by a tropical sun. Water is scarce and contested; wood is so rare that "some art is requisite to preserve and propagate the element of fire." There are no navigable rivers. The highlands bordering the Indian Ocean are more fertile, with wood, water, temperate air, and fruits; frankincense and coffee attracted merchants. Gibbon notes that the classical division into sandy, stony, and happy Arabia is "unknown to the Arabians themselves"—a striking admission that the familiar geography is a Greek/Latin construct, not native.
Population and modes of life. Gibbon argues that population is "regulated by the means of subsistence," so Arabia's vast peninsula might be outnumbered by a single fertile province. Along the coasts, primitive savages (Icthyophagi, or fish-eaters) wandered "without arts or laws, almost without sense or language." Most Arabs, however, "rose at once" from savagery to pastoral life, and Gibbon claims the modern Bedoweens are essentially unchanged since the age of Moses or Mahomet—same tents, same animals, same migrations. This is an assertion of timelessness, not an argument supported by evidence.
The horse and the camel. Arabia is "the genuine and original country of the horse"; European breeds derive from Arabian blood. Bedoweens preserve the "purest race" with "superstitious care." The camel is a "sacred and precious gift": it can travel days without food or water, storing water in a "fifth stomach." Nearly every part is useful: milk, meat, urine (for salt), dung (for fuel), and hair (for garments and tents).
Mecca. Gibbon stresses the paradox of its eminence: the city was small (never exceeding "the size and populousness of Marseilles"), situated in a barren plain at the foot of three sterile mountains, with rocky soil, brackish water from the holy well of Zemzem, distant pastures, and grapes imported from seventy miles away. "Some latent motive, perhaps of superstition, must have impelled the founders." The Koreishites, who ruled Mecca, compensated for agricultural poverty through trade. Gibbon details their commercial network: the seaport of Gedda gave access to Abyssinia; African goods crossed the peninsula to Gerrha or Katif; and from there, with Persian Gulf pearls, goods floated on rafts to the Euphrates. Mecca sat roughly equidistant—a month's journey—between Yemen (winter caravan) and Syria (summer caravan).
The independence of the Arabs. Gibbon is sharply critical of the apologetic use of the Arabs' "perpetual independence": "the arts of controversy transform this singular event into a prophecy and a miracle, in favor of the posterity of Ismael." He calls this reasoning "as indiscreet as it is superfluous." The exceptions are substantial: Yemen was subdued successively by Abyssinians, Persians, Egyptian sultans, and Turks; Mecca and Medina "have repeatedly bowed under a Scythian tyrant"; and the Romans held a province of Arabia. Yet Gibbon maintains the qualified version: these exceptions were "temporary or local." The body of the nation escaped the great empires—Sesostris, Cyrus, Pompey, Trajan all failed to conquer Arabia.
Gibbon's causal account is material and cultural, not providential. First, military culture arises from pastoral life: "The patient and active virtues of a soldier are insensibly nursed in the habits and discipline of a pastoral life." Second, historical memory matters: "The long memory of their independence is the firmest pledge of its perpetuity." Third, domestic feuds are suspended against a common enemy. Fourth, strategic retreat works: horses and camels can cover 400–500 miles in eight to ten days; the Arabs vanish before a conqueror, and "the secret waters of the desert elude his search." Fifth, the desert shields settled Arabia: the Bedouin barrier protected the "happy Arabia," whose inhabitants were "enervated by the luxury of the soil and climate."
Political structure. Gibbon describes Arab governance as hereditary but precarious. Sheikhs and emirs descend within chosen families, but succession is "loose and precarious," favoring the most worthy or aged. Authority rests on persuasion, not coercion—"the opinion of their wisdom and integrity." Abusive princes are quickly abandoned, since "the desert is open" and tribes are held by "mutual and voluntary compact."
Social character. Gibbon presents the Arab as psychologically distinctive: grave, sober, concise in speech, rarely laughing, stroking his beard as "the venerable symbol of manhood." The darker side: "Stranger = enemy"; the Ismaelite ideology that fertile climates were unjustly assigned to others; theft and trade equally practiced; blood revenge with feuds spanning fifty years. Honor wounds (women, beards) outweigh actual injuries. An annual truce of two to four months sheathed swords.
Civilizing influences. Language: Arabic shares a stock with Hebrew, Syriac, and Chaldaean; Mecca's dialect was preferred. Gibbon marvels at the vocabulary—"fourscore names of honey, the two hundred of a serpent, the five hundred of a lion, the thousand of a sword"—committed to memory by an illiterate people. Poetry: Poets were historians and moralists. The annual fair hosted poetry competitions; the seven "golden" poems hung in the Kaaba are noted. Hospitality: The Bedouin tent offers strangers "kind and respectful" treatment.
Religion. Gibbon presents astral religion as an almost rational response to the visible heavens—the stars display divinity, eternity, and order. The Arabs' "school" was "a clear firmament and a naked plain." Gibbon cites Diodorus Siculus on the Kaaba's antiquity and gives architectural details. He stresses that the pilgrimage rituals—encircling the Kaaba seven times, kissing the black stone, visiting mountains, throwing stones at Mina, sacrificing animals—were "invented and practised by the superstition of the idolaters." The Kaaba contained 360 idols. The black stone itself, he says, is "deeply tainted with the reproach of an idolatrous origin." Arabs practiced human sacrifice. They abstained from pork and practiced circumcision at puberty—customs "silently transmitted" to Muslim posterity.
Religious diversity. Gibbon's central claim is that Arabia's political and religious freedom attracted persecuted sects fleeing neighboring empires. He catalogs four major religious communities: Sabians (descended from Chaldaean astronomy), Magians (Zoroastrians), Jews (settled 700 years before Muhammad's death), and Christians (Catholic, Marcionite, Manichaean, Jacobite, and Nestorian missionaries all active). A "fundamental article of faith" shared by these learned strangers: belief in one supreme God who revealed himself through angels and prophets.
Muhammad's lineage and early life. Gibbon explicitly rejects the Christian calumny of Muhammad's "base and plebeian origin," arguing this actually exalts his merit. His Ismaelite descent was "a national privilege or fable," but he could claim many generations of genuine nobility from the tribe of Koreish and family of Hashem, hereditary guardians of the Caaba. Muhammad was born at Mecca in 569. He lost father, mother, and grandfather in early infancy; his inheritance was five camels and an Aethiopian maid. At twenty-five, he entered the service of Cadijah, a wealthy widow, who married him. At forty, he "assumed the title of a prophet."
The literacy question. Gibbon insists Mahomet was illiterate, citing the Koran itself and the unanimous testimony of early Muslim authorities. He explicitly rejects the contrary argument of Mr. White, who claimed literacy to prove imposture. Gibbon's reasoning: two short trading journeys to Syrian fairs could not have imparted such rare knowledge; Mahomet would not have dropped the mask in deliberate treaty-making; and his own family converts would have detected hypocrisy.
The Syrian journeys. Gibbon directly attacks the romanticized account of Count de Boulainvilliers, who imagined Mahomet as a philosophical traveler observing the weakness of Persian and Roman empires. Gibbon's "more accurate inquiry" establishes that Mahomet's two Syrian trips were confined to the fairs of Bostra and Damascus, that he was only thirteen on the first, and that he returned as soon as he had sold Cadijah's merchandise. Gibbon concludes: "he could not perceive, in the life or writings of Mahomet, that his prospect was far extended beyond the limits of the Arabian world."
The Islamic creed. Gibbon presents Islam's core as "an eternal truth, and a necessary fiction": one God, and Mahomet as his apostle. The unity of God is, for Gibbon, a genuine philosophical achievement—"a creed too sublime, perhaps, for our present faculties." He notes that a "philosophic theist might subscribe" to it, though he observes the difficulty: once you abstract from God all time, space, motion, matter, sensation, and reflection, "what object remains for the fancy, or even the understanding?"
The Koran. Gibbon contrasts Christian scripture—where divine inspiration coexisted with human reason—with Muhammad's claim that the Koran is a "simple edition" of an uncreated, eternal text. He notes the convenient doctrine of abrogation: later passages can override earlier ones, eliminating contradiction. The historical transmission is described: fragments recorded on palm-leaves and shoulder-bones, collected two years after Muhammad's death by Abubeker, revised under Caliph Othman in the thirtieth year of the Hegira.
Gibbon is openly dismissive of the Koran's literary merits. He argues that Muhammad's challenge to imitate a single page works only on "a devout Arabian" whose ear is attuned to the music of sounds and whose ignorance prevents comparison with human genius. To the "European infidel," the Koran is "an endless incoherent rhapsody of fable, and precept, and declamation." He makes a pointed rhetorical comparison: if the Koran exceeds human capacity, then the Iliad and the Philippics must be attributed to "some superior intelligence"—an ironic reductio.
The miracles question. Gibbon highlights a tension: Muhammad, pressed by the Koreish for miracles, refused, appealing instead to internal proofs and divine providence. Gibbon interprets Muhammad's "modest or angry tone" as betraying "weakness and vexation," and notes these passages "established, beyond suspicion, the integrity of the Koran"—they are so unflattering they must be authentic. Later Muslims grew more credulous with distance from events. Gibbon catalogs legendary miracles: trees meeting him, stones saluting him, water from his fingers, a groaning beam, a complaining camel, a poisoned shoulder of mutton. He recounts the nocturnal journey (Borak, seven heavens, the touch of God's hand) and the moon-splitting legend.
The three religious duties. Gibbon presents Muhammad's precepts as "a more simple and rational piety" than the superstitions he swept away. Prayer: fifty daily prayers were commanded, reduced to five at Moses's advice. The kebla initially toward Jerusalem, then fixed on Mecca. Islam has "no priesthood or sacrifice"—the independent spirit of fanaticism despises "the ministers and the slaves of superstition." Fasting: Muhammad rejected monastic asceticism but instituted the thirty-day Ramadan fast. The prohibition of wine was made "a positive and general law." Gibbon concludes the legislator "cannot surely be accused of alluring his proselytes by the indulgence of their sensual appetites." Alms: Islam's charity extends to animals, and Muhammad is "perhaps the only lawgiver who has defined the precise measure of charity": a tenth of revenue, enlarged to a fifth if conscience accuses one of fraud.
Islamic eschatology. Gibbon describes Muhammad's doctrine of bodily resurrection, noting Egyptian antecedents but observing that Muhammad more philosophically relied on divine omnipotence to reassemble scattered atoms. The final judgment was modeled on "the Magian picture" and "too faithfully" copied the slow procedures of an earthly tribunal. Non-Muslims, however virtuous, face eternal torment; Muhammad's tears over his mother's grave illustrate the tension between humanity and enthusiasm. Gibbon describes the sensual paradise—Houris, palaces, wine, luxury—with evident skepticism, noting that "too much of our present enjoyments is obtained from the relief, or the comparison, of evil."
Muhammad's early mission. Gibbon recounts the initial conversions: wife Cadijah, servant Zeid, cousin Ali (aged fourteen), and Abubeker, whose wealth and veracity lent credibility. Ten respectable Meccans followed. Three years produced only fourteen proselytes. Gibbon emphasizes the "slow and painful progress" of a religion that would later "overspread the East and the West."
Source criticism. Gibbon's central methodological point is that all existing biographies of Muhammad are corrupted by the author's prior agenda: Humphrey Prideaux wrote to expose Muhammad as an "impostor," while Comte de Boulainvilliers wrote to present him as a "hero." His preferred authorities are Abulfeda (1273–1331), an "enlightened" prince of Hamah, and Al Jannabi (d. ca. 1556), a "credulous doctor"—both translated by Jean Gagnier. Gibbon makes a damaging concession: both are modern historians, and neither can appeal to any writer of the first century of the Hegira. The earliest extant Muslim biographical tradition is separated from Muhammad's lifetime by centuries. Gibbon does not resolve this problem; he merely flags it.
The turn to holy war. Gibbon's central argument is that Muhammad's shift to military conquest was not a corruption of his original mission but a natural evolution driven by circumstance. He states bluntly that Muhammad's "former moderation was the effect of weakness," framing religious toleration as a strategic posture rather than principle. Gibbon grounds the military turn in natural law: every man may defend person and possessions, repel enemies, and seek "reasonable satisfaction and retaliation." Since Muhammad had been "despoiled and banished" unjustly, his war-making was legally justified. Divine revelation then supplied what human right lacked—the Koran's "fiercer and more sanguinary tone" authorized propagation of religion by the sword.
A notable feature is Gibbon's comparative treatment of scripture. He argues Muhammad could "appeal with more propriety" to Moses and the Hebrew kings than to Jesus, noting that Hebrew military laws are "still more rigid" than Muhammad's. He dismisses the Gospel's "sword" text as ambiguous, distinguishing Christ's "patient and humble virtues" from the "intolerant zeal of princes and bishops." This is significant: Gibbon, an Enlightenment skeptic, is more critical of Christian holy war than of Muhammad's, which he treats as historically intelligible.
The battles. Gibbon narrates three engagements: Beder (Muhammad's 313 men defeated 950 Koreish; Gibbon reports the supernatural elements—Gabriel, three thousand angels, the handful of sand—with evident skepticism, noting that commentators admit the angels "were not visible to any mortal eye"); Ohud (a defeat caused by Muslim archers disobeying orders to pursue spoil; Muhammad was wounded, two teeth shattered; the enemy's women mutilated bodies, with Hind tasting the entrails of Hamza); and the Ditch (a ten-thousand-man siege failed after twenty days, broken by weather and internal dissension).
The Jewish campaigns. Gibbon recounts three major conflicts with Jewish tribes near Medina. Against the Kainoka, after an "accidental tumult," Muhammad demanded conversion or battle; after fifteen days, he spared their lives but confiscated their wealth and exiled seven hundred families to Syria. The Nadhirites, accused of conspiring to assassinate Muhammad, were besieged and granted an "honorable capitulation." The Koraidha, after joining the Koreish war, surrendered after twenty-five days; an elder pronounced their death sentence, and seven hundred Jews were dragged to the marketplace and buried alive while Muhammad watched "with an inflexible eye." At Chaibar, the chief was tortured to reveal hidden treasure; Jews were permitted to remain as tenant farmers under precarious toleration.
Chapter LI: Conquests by the Arabs (Parts I–VII)¶
Gibbon opens this chapter by arguing that the death of Mahomet nearly undid his work: the Arabs’ “revolution” had not changed their character, and the new faith’s hold was fragile. He narrates the suppression of apostasy, especially the defeat of the rival prophet Moseilama, and then pivots to explain why the early caliphs did not personally lead armies. Their austerity—Abubeker’s three gold pieces, Omar’s tattered gown—is presented as virtue, and Gibbon credits the “spirit of the nation” rather than the chiefs for the conquests. He also insists that the Saracens’ success owed much to the “weakness of their enemies”: the Persians, Romans, and European barbarians were all in degenerate disorder, and stronger empires would have repelled the “naked Saracens.” The chapter then surveys the conquests of Persia, Syria, Egypt, Africa, and Spain, and closes with a portrait of the caliphs as absolute monarchs whose empire stretched from India to the Atlantic, unified by the Koran’s language and law.
Gibbon’s argument is essentially providential in reverse: Islam’s rise was less a miracle than a symptom of surrounding decay. His admiration for early caliphal frugality is genuine but romanticized, and he glosses over the violence of conquest with phrases like “torrent of fanaticism.” His claim that the Arabs were “naked” is rhetorical exaggeration, not description. The chapter’s treatment of Christians under Muslim rule is brief and largely legalistic, noting restrictions and occasional persecution without deep analysis. Gibbon’s sources are acknowledged as thin—he complains of “blindness and insufficiency” in his guides—yet he proceeds with confident synthesis. Worth noting: his framing of Muslim conquest as enabled by Christian and Persian weakness flatters Roman decline as the real subject, which is the book’s larger agenda.
Chapter LII: More Conquests by the Arabs (Parts I–V)¶
Gibbon opens this chapter by framing Arab expansion as a near-miraculous run of success that threatened to engulf the temperate zone, and he sets himself the task of explaining how Christendom survived. He narrates the first Arab siege of Constantinople (c. 673–680), stressing that the city’s walls, Greek discipline, and “artificial fire” (Greek fire) repelled a seven-year effort, after which a humiliating tribute was imposed on the caliph. He then moves through the Arab invasion of France and their defeat by Charles Martel, the internal civil war between the Ommiades and Abbassides, and the cultural and administrative achievements of the caliphate—including the minting of an Islamic coinage and the possible adoption of Indian numerals. The chapter closes with the later decay of the caliphate and the partial recovery of the Greek emperors, who retook Antioch and Cyprus.
Gibbon’s argument is that Arab success was driven by religious zeal and military confidence, but that their empire carried the seeds of its own division—through dynastic strife, luxury, and overextension. He treats the survival of Constantinople and Gaul as providential for European civilization, and he is openly admiring of Arab learning and administration even while condemning their “yoke.” His judgements are worth noting for their bias: he repeatedly calls Islam a “religion of the Koran” in a dismissive tone, treats the Prophet’s sayings as “genuine or fictitious” without resolving the question, and dismisses a vision revealing Abu Ayub’s tomb as “the manufacture of every religion.” He also indulges in casual orientalism, describing caliphal luxury as decadent and the Arabs as fanatics. His chronology is shaky—he flags the inconsistent dates for the siege himself—and his reliance on Greek chroniclers over Arabic sources is evident. Read him as a synthesis, not a neutral account.
Chapter LIII: Fate of the Eastern Empire (Parts I–IV)¶
Gibbon opens the chapter by treating the tenth-century Byzantine emperor Constantine Porphyrogenitus’s writings as a rare "ray of historic light," but he immediately qualifies this praise. He argues that the emperor’s four didactic works—on ceremonies, provinces, tactics, and administration—promise more than they deliver. The Basilics are a "broken copy" of Justinian’s law, corrupted by bigotry; the Tactics are derivative and confused, mixing incompatible institutions; the book of ceremonies is "tedious yet imperfect" pageantry. Gibbon’s key critical move is to dismiss the value of these texts for real history: they omit the population, revenue, and military numbers he wants, leaving only "traditionary fables" and epigrams. He does credit the administrative treatise for its accurate geography of barbarian nations, and he praises the Frankish bishop Liutprand’s account of Constantinople as lively and free, in contrast to Greek insularity.
The chapter’s broader argument is that Byzantine decline was cultural and psychological. Gibbon claims the Greeks, isolated from both Arab and Frankish competition, lost the "emulation" that drives progress; alone in the universe, they "fainted in the race." He is openly contemptuous of their literature—"political verses" that confound prosody—and their superstition, which destroyed "moral evidence." This is Gibbon at his most ideological: he treats European rivalry as the engine of civilization and reads Byzantine stagnation as self-inflicted, with little sympathy for the empire’s actual constraints. His evidence is thin, resting on rhetorical contrast rather than sustained analysis.
Chapter LIV: Origin and Doctrine of the Paulicians (Parts I–II)¶
In this chapter, Gibbon traces the origins, doctrine, and fate of the Paulicians, a sect he presents as a proto-Protestant movement. He describes how Constantine of Mananalis, inspired by a genuine New Testament, rejected images, relics, the cross, and the veneration of Mary and the saints, and even dismissed the Old Testament. Gibbon argues that the Paulicians were not true Manichaeans, despite being labeled as such, though he concedes they held a dualist belief in two principles—a good God and an evil creator of the material world. He then recounts their persecution by the Greek emperors, their revolt in Armenia, and their transplantation to Thrace, from where their influence spread westward. Gibbon’s central argument is that the Paulicians preserved a simpler, more rational Christianity that anticipated the Reformation, and he explicitly links them to the later Protestant break with Rome. His judgement is worth noting for its bias: he is openly sympathetic to their rationalism and hostile to the “superstition” of the Catholic and Orthodox churches, using the Paulicians as a stick to beat ecclesiastical authority. He also criticizes the Reformation’s own intolerance, citing Calvin’s execution of Servetus as a scandal, and laments that even reformers failed to embrace full toleration. The chapter is less a neutral history than a vehicle for Gibbon’s Enlightenment critique of religious dogma and persecution.
Chapter LV: The Bulgarians, the Hungarians and the Russians (Parts I–III)¶
Gibbon opens this chapter by dismissing the Bulgarians, Hungarians, and Russians as "swarms of savages" whose "names are uncouth, their origins doubtful, their actions obscure," and whose "valor [was] brutal"—a judgement he applies wholesale before examining any of them. He then traces the Bulgarians from their obscure origins to their settlement south of the Danube, noting their adoption of Slavonic language and their eventual Christianization. Their one notable achievement, he reports, was killing Emperor Nicephorus in battle and turning his skull into a drinking cup—a detail he uses to illustrate their "Scythian wilderness" manners, though he concedes these were "softened" by Greek contact. Gibbon's account of the Hungarians and Russians is largely a narrative of invasions repelled by the Byzantine throne, which he credits with "repelling and surviving their disorderly attacks." His central argument is that these peoples mattered only insofar as they threatened or interacted with civilization; their own histories are treated as footnotes to Byzantine survival. The chapter closes with a qualified endorsement of Christian conversion, which he admits brought "temporal benefits" by curbing piracy and introducing "the rudiments of art and science"—but he immediately undercuts this by noting that Byzantine influence failed because that empire was "servile, solitary, and verging to a hasty decline." Gibbon's contempt for his subjects is consistent and explicit; he never treats them as worthy of serious historical attention on their own terms, and his framing of "savages" versus "civilization" is unapologetically partisan.
Chapter LVI: The Saracens, the Franks and the Normans (Parts I–V)¶
In this chapter, Gibbon narrates the collapse of Byzantine and Lombard power in southern Italy and its replacement by Norman adventurers. He opens with the three-way struggle among Greeks, Saracens, and Franks, using the siege of Bari to dramatize the mutual contempt between the Eastern and Western emperors—quoting Lewis II’s boastful letter at length. Gibbon then traces the Normans’ rise from mercenary bandits to conquerors, focusing on Robert Guiscard’s military genius and his brother Roger’s conquest of Sicily. He credits the Normans’ success to their ferocity and discipline against the decadent Greeks and divided Lombards, and he treats their kingdom as a brief, brilliant anomaly. The chapter closes with the dynasty’s extinction: the German emperor Henry VI seizes Sicily, plunders Palermo, and violates royal tombs, while the Saracen colony at Nocera is eventually exterminated by the house of Anjou.
Gibbon’s argument is that the Normans were the last vigorous barbarians, whose energy exposed the hollow pretensions of both Constantinople and the papacy. His judgment is frankly admiring: he presents Guiscard as a heroic figure and the Norman state as a product of individual will rather than institutions. But his admiration is selective—he glosses over Norman brutality toward Greeks and Muslims, and he treats the Saracens mainly as pirates or pawns. His reliance on rhetorical set-pieces (the self-devoted patriot, the castration jest) shows his taste for anecdote over analysis, and he concedes the repetition of such stories “may sprinkle some doubts” on their truth. The chapter is vivid but tendentious: Gibbon’s Normans are less historical actors than instruments of his larger thesis about barbarian vitality versus imperial decay.
Chapter LVII: The Turks (Parts I–III)¶
In this chapter Gibbon narrates the rise of the Seljuk Turks, from their origins as nomadic shepherds to their conquest of Persia and Asia Minor, culminating in the defeat of the Byzantine emperor Romanus Diogenes at Manzikert. He opens with the earlier Ghaznavid dynasty, focusing on Mahmud of Ghazna, whose twelve expeditions into India Gibbon treats as a mix of holy war and plunder—he recounts the destruction of the Somnath temple and the idol’s ransom with evident relish, quoting Mahmud’s refusal to be “a merchant of idols.” Gibbon then pivots to the Seljuks proper: Togrul’s protection of the Abbasid caliphs, Alp Arslan’s capture of Romanus, and the magnificence of Malek Shah. The chapter closes with the Seljuk occupation of Jerusalem under the Ortokid emirs, where Gibbon describes the oppression of pilgrims and the desecration of holy sites as the proximate cause of the First Crusade.
Gibbon’s argument is that the Turkish conquests were a necessary precondition for the Crusades: the Seljuks replaced the relatively tolerant Fatimid caliphs with “the iron yoke of the strangers of the North,” and this new barbarism, not the earlier sacrilege of Hakem, finally “vibrated to the heart of Europe.” His judgement is characteristically ironic—he notes that the pilgrims’ suffering was “trifling” compared to earlier outrages, yet it provoked a vastly greater response, which he attributes to a new “spirit of religious chivalry and papal dominion.” Be critical: Gibbon’s account of Mahmud is hagiographic, praising his “justice and magnanimity” while glossing over mass slaughter as mere “paths of blood,” and his numbers (ten million sterling ransom) are uncritically repeated despite his own footnotes casting doubt on them.
Chapter LVIII: The First Crusade (Parts I–V)¶
Gibbon opens Chapter LVIII with the First Crusade’s origin in the fanaticism of Peter the Hermit, a figure he portrays as physically contemptible but rhetorically potent—"his ignorance of art and language was compensated by sighs, and tears, and ejaculations." Gibbon’s argument is that the crusade was not a spontaneous religious outpouring but a calculated papal project: Pope Urban II, a Frenchman, exploited the enthusiasm Peter stirred, using the Council of Clermont to redirect feudal violence outward while consolidating his own authority against the German emperor and the French king. Gibbon stresses the political motives beneath the piety, noting Urban’s "latent motive of affection or vanity" in choosing France. The chapter then follows the march to Constantinople, the dealings with Emperor Alexius, and the conquests of Nicaea, Antioch, and Jerusalem, culminating in Godfrey of Bouillon’s kingship. Gibbon’s judgement is consistently skeptical: he treats the crusaders’ zeal as manipulated passion, the Greek emperor’s policy as shrewd but betrayed, and the Latin kingdom’s institutions—the Assise of Jerusalem—as a feudal transplant that codified hierarchy, with slaves valued at a fraction of a war-horse. His critical edge is sharpest on the crusaders’ brutality and the gap between their stated mission and their conduct. Worth noting: Gibbon’s irony can shade into condescension, and his reliance on Latin chroniclers means he largely adopts their framing of Muslim opponents as mere obstacles.
Evidence, examples, and intellectual basis¶
Gibbon's method combines source criticism with comparative historical reasoning. He explicitly evaluates his authorities: Abulfeda is "enlightened," Al Jannabi "credulous," the Liber Pontificalis "barbarous" but "authentic," and the Greek sources on the papal rebellion "apt to confound the times and actions of two Gregories." He rejects Prideaux and Boulainvilliers as corrupted by prior agendas—one writing to expose an impostor, the other to celebrate a hero.
His evidence ranges widely: the forged Donation of Constantine and the letter of St. Peter; the Edessa legend, which he dates by noting Eusebius "most strangely forgets the picture"; the Koran's internal contradictions, which he treats as evidence of authenticity since they are "so unflattering they must be authentic"; and the two surviving letters of Gregory II, which he reads as "the portrait, or at least the mask, of the founder of the papal monarchy."
Gibbon's intellectual basis is materialist and psychological. Population is "regulated by the means of subsistence"; military virtue arises from pastoral life; the Arabs' independence is explained by geography, not providence. His comparative framework is consistently Enlightenment: he measures Islam against Christianity, Muhammad's military laws against Hebrew scripture, and Byzantine sterility against Western dynamism.
Practical recommendations¶
Gibbon offers no explicit practical advice, but his historical judgments imply clear lessons for readers. First, treat institutional claims with suspicion: the Donation of Constantine, the forged letter of St. Peter, and the Holy Lance all shaped history despite being fraudulent—"productive of the most beneficial effects" for their inventors. The lesson is that legitimacy is manufactured, not discovered.
Second, distinguish between the mask and the face of power. Gregory II's letters exhibit "the portrait, or at least the mask" of papal monarchy; Charlemagne's imperial title added nothing to his actual patrician authority. Institutions persist through ceremony and pretense long after their substantive basis has vanished.
Third, recognize that religious enthusiasm produces unintended political consequences. The iconoclast controversy created papal power; the crusade indulgence channeled violence into holy war. Reformers should expect their movements to escape their intentions.
Fourth, prefer moderate positions in controversy, since "the moderate party" stands "exposed to the fire of both sides"—yet Gibbon's own practice shows the value of skeptical detachment from all partisans.
What is persuasive¶
Gibbon's most persuasive arguments are those where he combines source criticism with structural analysis. His treatment of the papal rebellion is exemplary: he shows how Byzantine, Catholic, and Protestant sources all distort the same facts, then reconstructs a plausible narrative from the surviving documents. His dating of the Edessa legend—between 521 and 594, most probably after the siege of 540—is a model of critical reasoning.
His account of Muhammad's turn to holy war is persuasive because it treats religious change as historically intelligible rather than miraculous or diabolical. The claim that "former moderation was the effect of weakness" is psychologically plausible and grounded in the documented sequence of events. Similarly, his "weakness of enemies" thesis—that Arab conquests succeeded through Persian demoralization and Byzantine factionalism—explains more than military superiority alone.
His analysis of the crusade indulgence as emerging from penitential economy is compelling: he traces how commutation, flagellation, and military substitution created a system where sinners could atone by killing infidels. The structural argument about German emperors—that they lacked the resources for true empire, producing the "monster with a hundred heads"—remains a powerful explanation of medieval German fragmentation.
Limitations, contested claims, and what is missing¶
Gibbon's most obvious limitation is his confessed source problem: no writer of the first century of the Hegira survives, and both his preferred authorities are separated from Muhammad by centuries. He flags this but cannot resolve it. His treatment of Muhammad's literacy is similarly contested: he rejects Mr. White's argument on plausibility grounds, but the evidence is genuinely ambiguous.
His skepticism about religious claims, while consistent, sometimes becomes dismissive. He calls the Koran "an endless incoherent rhapsody" and dismisses monastic martyrdom without examining "how far the monks provoked, nor how much they have exaggerated, their real and pretended sufferings." His assertion that the Bedoweens are "essentially unchanged since the age of Moses" is an unsupported claim of timelessness.
His treatment of women is notably absent: the mutilation of bodies at Ohud, the fate of female captives, and the status of women under Islam receive little sustained analysis. His account of the Paulicians as "seeds of the Reformation" is anachronistic, projecting later Protestant concerns backward. And his counterfactual about the Koran being "taught in the schools of Oxford" reveals a Whiggish sense that history's actual course was preferable.
Bottom line¶
Volume 5 of Decline and Fall is Gibbon at his most characteristic: sweeping in scope, caustic in tone, and relentlessly skeptical of religious claims. His central achievement is to show that the Roman Empire's transformation was driven by religious controversy, barbarian conquest, and the rise of new powers—not by any single catastrophe. The iconoclast controversy, treated by most historians as theological trivia, becomes in his hands the hinge that produced papal power, the Frankish alliance, and the restoration of the Western empire.
His method is the great strength: he reads sources against their authors' intentions, exposes forgeries while acknowledging their historical efficacy, and explains religious movements through material and psychological causes. His account of Islam's rise—geography, social structure, religious diversity, Muhammad's career, the turn to holy war—remains a model of Enlightenment historiography, critical yet historically intelligible.
The limitations are equally clear: his source base for early Islam is thin and he knows it; his skepticism sometimes curdles into dismissal; his anachronisms (the Paulicians as proto-Protestants) reveal his own commitments. Yet the volume's enduring value lies in its questions: How do religious movements produce political transformation? How do conquerors become heirs of the civilizations they defeat? Why do some institutions decay while others endure?
Gibbon's answer is that decline is never simple collapse but always metamorphosis—the Roman world did not die but became something else, through forces its actors neither intended nor foresaw. The volume is a masterpiece of historical irony, and its assessment of the period is completed: the decline and fall of Rome was not a tragedy but a transformation, driven by superstition, ambition, and the unintended consequences of human action.