Twenty years after they had been driven away from Constantinople, the Arabs surged back into Asia Minor. The Byzantine emperor Leo III, the Isaurian, met the new invasion at Acroinum (Akroinon), in ancient Phrygia, in 739. In a great battle the Moslems of the Hisham caliphate were defeated and turned back toward Damascus. This check in Asia Minor followed the blunting of the moslem thrusts on the two extremes of their empire - France and China- and the was aggression of the Ommiad Dynasty.