William of Tyre (Latin: Willelmus Tyrensis; c. 1130 – 29 September 1186) was a medieval prelate and chronicler. As archbishop of Tyre, he is sometimes known as William II to distinguish him from his predecessor, William I, the Englishman and former Prior of the Church of the Holy Sepulchre, who was Archbishop of Tyre from 1127-1135. He grew up in Jerusalem at the height of the Kingdom of Jerusalem, which had been established in 1099 after the First Crusade, and he spent twenty years studying the liberal arts and canon law in the universities of Europe.
Following William's return to Jerusalem in 1165, King Amalric made him an ambassador to the Byzantine Empire. William became tutor to the king's son, the future King Baldwin IV, whom William discovered to be a leper. After Amalric's death, William became chancellor and archbishop of Tyre, two of the highest offices in the kingdom, and in 1179 William led the eastern delegation to the Third Council of the Lateran. As he was involved in the dynastic struggle that developed during Baldwin IV's reign, his importance waned when a rival faction gained control of royal affairs. He was passed over for the prestigious Patriarchate of Jerusalem, and died in obscurity, probably in 1186.
William wrote an account of the Lateran Council and a history of the Islamic states from the time of Muhammad. Neither work survives. He is famous today as the author of a history of the Kingdom of Jerusalem. William composed his chronicle in excellent Latin for his time, with numerous quotations from classical literature. The chronicle is sometimes given the title Historia rerum in partibus transmarinis gestarum ("History of Deeds Done Beyond the Sea") or Historia Ierosolimitana ("History of Jerusalem"), or the Historia for short. It was translated into French soon after his death, and thereafter into numerous other languages. Because it is the only source for the history of twelfth-century Jerusalem written by a native, historians have often assumed that William's statements could be taken at face value. However, more recent historians have shown that William's involvement in the kingdom's political disputes resulted in detectable biases in his account. Despite this, he is considered the greatest chronicler of the crusades, and one of the best authors of the Middle Ages. SOURCE: Wikipedia