Roman legions under Pompey conquered much of the Levant in 63 BC, inaugurating a period of Roman rule that lasted four centuries. In 106 AD, Emperor Trajan annexed Nabataea unopposed, and rebuilt the King's Highway which became known as the Via Traiana Nova road. The Romans gave the Greek cities of Transjordan–Philadelphia (Amman), Gerasa (Jerash), Gedara (Umm Quays), Pella (Tabaqat Fahl) and Arbila (Irbid)–and other Hellenistic cities in Palestine and southern Syria, a level of autonomy by forming the ''Decapolis'', a ten-city league. Jerash is one of the best preserved Roman cities in the East; it was even visited by Emperor Hadrian during his journey to Palestine.