John I Tzimiskes
The soldier emperors Nikephoros II Phokas (reigned 963–69) and John I Tzimiskes (969–76) expanded the empire well into Syria, defeating the emirs of north-west Iraq and reconquering Crete and Cyprus. At one point under John, the empire's armies even threatened Jerusalem, far to the south. The emirate of Aleppo and its neighbours became vassals of the empire in the east, where the greatest threat to the empire was the Egyptian Fatimid kingdom.