Early in the year A. D. 642, Alexandria surrendered to Amrou, the Islamic general leading the armies of Omar, Caliph of Baghdad. Long one of the most important cities of the ancient world and capital of Byzantine Egypt, Alexandria surrendered only after a long siege and attempts to rescue the city by the Byzantines. On the orders of Omar, Caliph of Baghdad, the entire collection of books (except for the works of Aristotle) stored at the Library of Alexandria were removed and used as fuel to heat water for the city's public baths. This is not the first time the library was damaged or destroyed. Originally built to house the massive collection of books accumulated by the Ptolemaic rulers of Egypt, the library had been devastated by fire several times. During Julius Caesar's Alexandrian campaign in 47 B. C., Caesar set fire to ships in the port which spread to the library, which was called the Museum at that time. In A. D. 391, riots instigated by fanatical Christians damaged the collection heavily. During the years between disastrous events, the library collection had been gradually restored. In 641, the Caliph of Baghdad exhibited the same spirit of religious fanaticism in ordering Amrou to burn the books stored there. It was a common occurrence for libraries in ancient times to be destroyed as a result of war. They were usually located near the royal palaces, which were often targeted for destruction by invaders or were the place where a monarch made a last stand. It was also common for these repositories of human knowledge to be deliberately destroyed. Just to show that this form of barbarism was not only a Muslim or a Christian phenomenon, the early Chinese emperor Q'in Shihuang Ti burned most of the scholarly books and put many Confucian scholars to death in the years between 220 and 206 B. C. This is a crude strategy used by any bigoted conqueror bent on depriving a people of their culture, heritage, and learning. The logic is that it is easier to enslave a people when you have first taken away their literature and left a generation or two of them in ignorance. The loss of the library at Alexandria was particularly grievous blow, though, because the works of so many Roman scholars. literary geniuses, and historians were destroyed. It would be another 850 years before technology made it possible to reproduce books in sufficient quantity to ensure the survival of at least a few copies in times of devastation.