On the morning of 29 May 1453, the Ottoman army of Sultan Mehmed II breached the land walls of Constantinople and took the city by storm, ending the Byzantine Empire — the surviving eastern half of the Roman state, governed in an unbroken line from the capital Constantine the Great had dedicated as New Rome on 11 May 330. The last emperor, Constantine XI Palaiologos, died in the fighting near the breach; his body was never identified with certainty. After a siege of roughly seven weeks, an empire that traced its authority to Augustus passed out of existence.
By 1453 that empire was already a husk. The polity Mehmed conquered was not the Mediterranean superstate of Justinian but a rump centered on a single decayed city, surrounded on every side by Ottoman territory and surviving largely on Ottoman sufferance. The decisive wound had been inflicted not by Muslims but by fellow Christians: the Fourth Crusade had sacked Constantinople in 1204, broken the empire into Latin and Greek fragments, and drained the strength it never recovered after the Greeks retook the city in 1261. What fell in 1453 had been dying for two and a half centuries.
The mechanism of the final conquest was a collision between an old technology and a new one. The Theodosian Walls, raised in the fifth century, had repelled assault for a thousand years and were the most formidable land fortification in the medieval world. Against them Mehmed brought the largest gunpowder siege train yet assembled, including a monstrous bronze bombard cast by the Hungarian engineer Orban. The walls that had defined the impregnability of Constantinople were, within weeks, reduced to a problem of arithmetic.
The fall reverberated far beyond the Bosporus. It severed the eastern land routes that had carried Asian goods to Europe through Constantinople, sharpening the search for sea passages that became the Age of Exploration; it scattered Greek scholars and manuscripts westward into a Renaissance hungry for them; and it gave the Ottomans an imperial capital they would rule for nearly five centuries. The conversion of the great church of Hagia Sophia into a mosque, ordered by Mehmed on the day of the conquest, fixed the moment in memory as the end of one age and the start of another.
In February 1258, the Mongol army of Hulagu Khan — a grandson of Genghis Khan — stormed Baghdad, the capital of the Abbasid Caliphate, and extinguished a dynasty that had claimed the leadership of the Sunni Muslim world for five centuries. The Mongols invested the city on or about 29 January, breached its walls within days, and accepted the surrender of the caliph al-Musta’sim on 10 February. The sack that followed killed an immense number of the city’s inhabitants, scattered or burned its great libraries, and left Baghdad a depopulated ruin. The caliph himself, the thirty-seventh and last of the Abbasid line, was executed on 20 February — rolled in a carpet and trampled to death by horses, by an account widely repeated, so that no royal blood would touch the ground.
The dynasty that ended had been founded in 750, when the Abbasids overthrew the Umayyads, and from its purpose-built capital at Baghdad, established in 762, it had presided over the most brilliant period of medieval Islamic civilization. By the thirteenth century, however, the caliphate’s real power had long drained away. For three hundred years the caliphs had reigned more than they ruled, their authority eclipsed first by Persian and then by Turkish military dynasties — the Buyids and the Seljuks — who held the caliph as a revered figurehead. What Hulagu conquered was a city and a symbol, not the empire of Harun al-Rashid.
The mechanism of the fall combined a vast, methodical war machine with a defender who had neither the force to resist it nor the realism to submit in time. Hulagu had been dispatched from Mongolia with an enormous army and explicit orders to subdue the Islamic heartland. Al-Musta’sim, by contrast, presided over a divided and reduced court, dismissed the danger, refused the Mongols’ demands, and failed to mobilize, even as his armies were destroyed outside the walls. His misjudgment did not cause the disparity of power, but it ensured that the disparity ended in massacre rather than negotiated surrender.
The consequences outlasted the rubble. The killing of the caliph left Sunni Islam without the office that had symbolically united it since the death of the Prophet, and the political shock of an Islamic capital destroyed by non-Muslim conquerors reverberated for generations. The destruction of Baghdad’s books and scholarship became, in later memory, the emblem of a lost golden age — though the city’s intellectual life was not annihilated as totally as legend holds, and libraries reopened within a few years. What was beyond dispute was that an institution more than five centuries old, and the city that had been the center of a world, were broken in a single fortnight.