In 324 AD , the Roman Empire split , and the Eastern Roman Empire – later known as the Byzantine Empire – continued to control or influence the region until 636 AD . Christianity had become legal within the empire in 313 AD and the official state religion in 390 AD , after Emperor Constantine converted to Christianity . Transjordan prospered during the Byzantine era , and Christian churches were built everywhere . The Aqaba Church in Ayla was built during this era , it is considered to be the world 's first purpose built Christian church . Umm ar-Rasas in southern Amman contains at least 16 Byzantine churches . Meanwhile , Petra 's importance declined as sea trade routes emerged , and after a 363 earthquake destroyed many structures , until it became an abandoned place . The Sassanian Empire in the east became the Byzantines ' rivals , and frequent confrontations sometimes led to the Sassanids controlling some parts of the region , including Transjordan
363 earthquake
Galilee earthquake of 363
Jordan