The Romans established the Decapolis, a league of ten cities in northern Jordan, Syria and Palestine, to facilitate the area’s commerce and to protect the far flung regions of their empire. Four of the cities of The Decapolis are in Jordan: Philadelphia (now Amman), Jerash (the best-preserved and most complete city of The Decapolis), Pella (Tabaqet Fahl), and Umm Qais (Gadara).