Complex sentence: All the cities in Asia Minor opened their doors to the Roman emperor, with only Tyana putting up some resistance before surrendering; this cleared the path for Aurelian to invade Syria, the Palmyrene heartland.
Split into simpler sentences: All the cities in Asia Minor opened their doors to the Roman emperor, with only Tyana putting up some resistance before surrendering. This cleared the path for Aurelian to invade Syria, the Palmyrene heartland.