Complex sentence: The entire area of the former diocese came under Sassanid occupation between 609 and 628, but it was retaken by the Emperor Heraclius until its irreversible lost to the Arabs after the Battle of Yarmouk and the fall of Antioch.
Split into simpler sentences: The entire area of the former diocese came under Sassanid occupation between 609 and 628, but was retaken by the Emperor Heraclius. Until its irreversible lost to the Arabs after the Battle of Yarmouk, and the fall of Antioch.