Ioannes I Tzimisces (924-976), Byzantine emperor (969-976). Of Armenian descent, Ioannes Tzimisces entered the imperial army and fought with Nicephorus against the Arabs in Cilicia and Syria. Handsome, though short, strong and well-known for his valiance and aptitude in archery, spearmanship and riding, having helped Nicephorus gain the throne, he was rewarded with the supreme command of Byzantine forces in the East. His ambition for the throne later led him into the conspiracy with his mistress, Theophano (the Emperor's wife), that led to the assassination of Nicephorus in December 969. Forced to do penance by Polyeuctus, patriarch of Constantinople, in order to receive the imperial crown, John banished Theophano to a convent, punished the murderers and abolished the laws of his predecessor that were prejudicial to the property of the Church.
His extension of Byzantine influence into the Balkans and Syria and maintenance of domestic tranquillity assured the prestige and stability of the empire for his immediate successors. Tzimisces strengthened the empire by coupling diplomatic skill with military strength. In 970 he married Theodora, sister of Constantine VII Porphyrogenitus, the legitimate claimant to the throne, to offset challenges to his rule at home.
When the Bulgars attacked the empire
in 971, he led his forces against their capital, captured their tsar, and forced them to
recognize Byzantine suzerainty. In July 971 he defeated the Russian prince Svyatoslav, ending
threats to Byzantine rule in the north. To preserve the Byzantine position in the West, he
arranged a marriage between one of his relatives and the future Holy Roman emperor Otto II.
Turning to the East, he reduced the Fatimid strength around Antioch in 974-975, taking Antioch,
Damascus, and other cities in Syria. Before he could retake Jerusalem he died, probably of
typhoid, on 10th January 976 and was succeeded by Basil Macedon II.