For five hundred years Baghdad was not merely a city but a symbol. Capital of the Abbasid Caliphate, the heart of Islam's "golden age," home of the very House of Wisdom where Aristotle, Ptolemy, and Indian mathematics were translated and enlarged. Here the unity of faith and learning seemed inscribed into the order of the world — the caliph was the axis around which the universe of the faithful held together. The first beat does not apply here: those who perished had built no idol; the node enters the law at the third beat — captivity and return. The caliph of the thirteenth century had long been a nominal figure, and the catastrophe did not come from within — this is pure conquest.
The collapse was swift and complete. In early 1258 the Mongol army of Hülegü approached the city. Caliph al-Musta'sim was offered surrender without bloodshed — he refused, relying on the inviolability of his office. The siege engines breached the fortifications in a matter of days; on the 10th of February the city fell. Then came slaughter and fire: the libraries were destroyed, and eyewitnesses recalled that the Tigris ran black with the ink of countless books thrown into the river. The caliph himself, as tradition has it, was put to death without "royal blood" being spilled outright — wrapped up and trampled. The five-century line of the Abbasids was cut short in a matter of weeks.
The captivity settled upon the land and upon the mind. Mesopotamia and Iran passed into the realm of the Ilkhanate; the heart of ancient learning sank into decline, and the Islamic world was left without the symbolic center around which its unity had gathered for centuries. Thus the beat of bondage is fulfilled: the blow fell not on the periphery but on the very core, and the wound went the deeper the more sacred the thing destroyed had seemed. A world accustomed to thinking Baghdad eternal suddenly discovered that it had lived with no second center in reserve.
The return came not as a resurrection of the fallen but as the transfer of life into new vessels. In 1260 at Ain Jalut the Mamluks of Egypt inflicted the first major defeat upon the Mongols and halted the wave. The centers of learning and power shifted to Cairo and Damascus, and later to the Ottomans and Istanbul. Baghdad did not rise again as it had been; in place of restoration, what survived was decanted into other forms. Herein lies the essence of return by the law of history: what is saved is not the stone nor the title but the living content — if it manages to find a new home before the flame goes out.