prologue and one chapter, so it is either unfinished or the rest of the pages were lost before the whole chronicle began to be copied. The first book begins with the conquest of Syria by Umar in the seventh century, but otherwise the work deals with the advent of the First Crusade and the subsequent political history of the Kingdom of Jerusalem. It is arranged, but was not written, chronologically; the first sections to be written were probably the chapters about the invasion of Egypt in 1167, which are extremely detailed and were likely composed before the Fatimid dynasty was overthrown in 1171. Much of the Historia was finished before William left to attend the Lateran Council, but new additions and corrections were made after his return in 1180, perhaps because he now realized that European readers would also be interested in the history of the kingdom. In 1184 he wrote the Prologue and the beginning of the twenty-third book. August C. Krey thought William's Arabic sources may have come from the library of the Damascene diplomat Usama ibn Munqidh, whose library was looted by Baldwin III from a shipwreck in 1154. Alan V. Murray, however, has argued that, at least for the accounts of Persia and the Turks in his chronicle, William relied on Biblical and earlier medieval legends rather than actual history, and his knowledge "may be less indicative of eastern ethnography than of western mythography." William had access to the chronicles of the First Crusade, including Fulcher of Chartres, Albert of Aix, Raymond of Aguilers, Baldric of Dol, and the Gesta Francorum, as well as other documents located in the kingdom's archives. He used Walter the Chancellor and other now-lost works for the history of the Principality of Antioch. From the end of Fulcher's chronicle in 1127, William is the only source of information from an author living in Jerusalem. For events that happened in William's own lifetime, he interviewed older people who had witnessed the events about which he was writing, and drew on his own memory. William's classical education allowed him to compose Latin superior to that of many medieval writers. He used numerous ancient Roman and early Christian authors, either for quotations or as inspiration for the framework and organization of the Historia. His vocabulary is almost entirely classical, with only a few medieval constructions such as "loricator" (someone who makes armour, a calque