The wars ranged across the eastern Mediterranean, initially concentrating on Syria, Palestine, Egypt, and North Africa. A major land frontier developed along the Taurus Mountains between Byzantine Anatolia and Muslim-controlled territories to the south and east, in areas now largely within Turkey and Syria. Fleets contested islands including Cyprus, Crete, and Sicily, and Arab forces attacked Constantinople. Mountain passes, fortified border districts, and sea routes connected the conflict's land and maritime theaters.