Furthermore, the veterans of two Roman legions were established in the city of Berytus by emperor Augustus: the 5th Macedonian and the 3rd Gallic Legions. Berytus's law school was widely known; two of Rome's most famous jurists, Papinian and Ulpian, were natives of Phoenicia and taught there under the Severan emperors. When Justinian assembled his Pandects in the 6th century, a large part of the corpus of laws was derived from these two jurists, and in AD533 Justinian recognised the school as one of the three official law schools of the empire. In 551, a major earthquake struck Berytus, causing widespread damage. The earthquake reduced cities along the coast to ruins and killed many, 30,000 in Berytus alone by some measurements. As a result, the students of the law school were transferred to Sidon. Salvage excavations since 1993 have yielded new insights in the layout and history of Roman Berytus. Public architecture included several bath complexes, Colonnaded Streets, a circus and theatre; residential areas were excavated in the Garden of Forgiveness, Martyrs' Square and the Beirut Souks. Middle Ages Beirut was conquered by the Muslims in 635. Prince Arslan bin al-Mundhir founded the Principality of Sin el Fil in Beirut in 759. From this principality developed the later Principality of Mount Lebanon, which was the basis for the establishment of Greater Lebanon, today's Lebanon. As a trading center of the eastern Mediterranean, Beirut was overshadowed by Acre (in modern-day Israel) during the Middle Ages. From 1110 to 1291, the town and Lordship of Beirut was part of the Kingdom of Jerusalem. The city was taken by Saladin in 1187 and recaptured in 1197 by Henry I of Brabant as part of the German Crusade of 1197. John of Ibelin, known as the Old Lord of Beirut, was granted the lordship of the city in 1204. He rebuilt the city after its destruction by the Ayyubids and also built the House of Ibelin palace in Beirut. In 1291 Beirut was captured and the Crusaders expelled by the Mamluk army of Sultan al-Ashraf Khalil. Ottoman rule Under the Ottoman sultan Selim I (1512–1520), the Ottomans conquered Syria including present-day Lebanon. Beirut was controlled by local Druze emirs throughout the Ottoman period. One of them, Fakhr-al-Din II, fortified it early in the 17th century, but the Ottomans reclaimed it in 1763. With the help of Damascus, Beirut successfully broke Acre's monopoly on Syrian