The century from the definitive capture of Crete (960) to the defeat by the Seljuk Turks at Manzikert (1071) illustrates the glorious apogee and beginning of decline of the Byzantine state. Up to the 920s, Byzantium was served by excellent generals and warrior emperors. The First was Nicephorus Phocas, who directed the conquest of Crete and capture of Candia, its capital. In the same years, Nicephorus' brother, Leo Phocas, was active in the East. Sayf al-Dawla, the Abbasid-Buyid Amir of Mosul, had captured Aleppo in Syria in 945, and had expanded to Damascus, Emesa, and Antioch. In 960, he sent a major expedition into Byzantine lands, at the same time as most Byzantine forces were in Crete. Leo allowed the Amir's forces to advance and take prisoners and plunder in Byzantine lands, while the Byzantines set up their forces at the key passes through the Taurus mountains that Sayf would need to return through. In November 961, Leo and Sayf's forces met, the latter being pulled into a well- planned Greek ambush. Sayf's forces were routed, and the Byzantine eastern frontier had been restored. In early 962, Leo led an offensive that regained fifty-five walled towns in southeastern Anatolia. In the spring, his forces went south into Syria, leaving nothing unburned or unplundered. Aleppo was eventually sacked and plundered, but left un-occupied, its Arab garrison deemed too small to be of danger. At this point, the Emperor Romanus II died, and in a protracted contest among various imperial claimants, Nicephorus Phocas emerged as Emperor by 963. He raised Leo to Imperial Court Marshal, and another prominent general, John Tzimisces, became commander-in-chief of Anatolian forces.
Nicephorus was occupied on three fronts: 1) the Eastern, Islamic; 2) the Northern, Bulgar-Russian; and 3) the internal front, comprising the Church, the Anatolian landed aristocracy, and the smallholding peasant-soldier class. He had the best success against the Turco-Arab Muslims. In 965, Byzantines recovered Tarsus, which Muslims had been using as a base for Cilician incursions. In the same year, he set his sights on Cyprus. For nearly 300 years, Caliphate and Byzantium had jointly occupied it. In 965, Nicephorus' armies occupied it totally, forming it into a Theme. Two years later Sayf al- Dawla died, and in 969 the holy city of Antioch returned to Byzantine possession after 332 years.
The northern front gave mixed results. In 965, Bulgar ambassadors arrived requesting the tribute that had been delivered to them ever since the late 920s when the Bulgar Czar at that time had married into the Byzantine family and furthered Christianization, in the process making his state an effective buffer against Magyars and Russians. Nicephorus refused the tribute, abused the ambassadors, and then advanced to the Bulgarian frontier, capturing several border towns. Not wanting to deplete troop numbers in the east, however, he elected not to invade Bulgaria himself. Instead, he made an agreement with the Viking-Russian Prince of Kiev Sviatoslav. In return for a cash gift, Sviatslov would subdue the Bulgars. Sviatoslav did this quite effectively, crumpling the Bulgar state and replacing it on the Byzantine border. By 969, when Bulgar Czar Peter died, the Russians were amassing forces right up against the Thracian border.
Nicephorus eventually lost his throne, due mostly to internal problems. A member of the Anatolian landholding aristocracy and a general, Nicephorus Phocas patronized these two groups at the expense of all other segments in the Empire, including the Church and the rural-urban masses. Regarding the former, though Nicephorus was rigorously puritanical, he was incensed by the large tracts of Anatolian land monasteries and churches controlled in such a way as to put them beyond state, Theme, and landholder access. He thus proscribed additional transfers of land to the Church. Further, in a particularly Byzantine foreshadowing of the Investiture Controversy, the Emperor decreed that new bishops would have to receive his personal approval for their appointments to be valid.
As regards the masses, though the backbone of the Themes was the mass of smallholding peasant soldiers, Nicephorus actually facilitated the large Anatolian landholders' expansion of their holdings in his effort to help the state treasury. When a tract came up for sale, first preference was given to the owners of the adjacent tract, after which the highest bidder was allowed access. The highest bidders, of course, were the already large landed gentry. Nicephorus also implemented harsh taxes to finance the military. The army in turn, especially in Constantinople, increasingly antagonized the urban populace through their uncouth behavior. Ultimately, though, it was not a general urban revolt, but a plot that ended Nicephorus' rule. Nicephorus' beautiful, conniving wife Theophano convinced him to recall to the capital John Tzimisces, an old boon companion recently fallen under a cloud. After his return, Theophano and John conspired to usurp the throne. On December 10, 969, John himself slipped into the palace and murdered the Emperor, assuming the purple the next day and ridding himself of Theophano to placate public and clerical opinion. Like his predecessor, John Tzimisces major concern were his neighbors to the north and east. In 970, Sviatoslav of the Russians went on the offensive, coming south of the Danube. Byzantine forces did not engage the enemy until they reached Arcadiopolis. After ambushing an advance guard of Pechenegs, the Imperial forces went on to utterly defeat the Russians. In the intervening two years, John dealt with internal revolts and claims to the throne on the behalf of the slain Nicephorus' relatives in the Phocas family as well as other prominent generals. In 972, however, John himself led armies to the old Bulgarian capital of Preslav and engaged the Russians in a fierce battle. Ultimately, the Russians broke under the thrusts of John's own elite forces, and so Preslav was later occupied by Greek forces around Easter 972. Sviatoslav fled and was finally defeated at Dristra on the Danube, in July 972. Bulgaria had been totally secured for Byzantium. The Bulgar Czar abdicated, its patriarchate was reduced to an archbishopric, and the region was absorbed as a province.
In 975, John turned his full attention to the East, where the Fatimid state had expanded its influence past Egypt into Syria. Tzimisces' campaigns here would represent the furthest extent of Byzantine reconquest in the Empire's history. By the fall of that year, most of Palestine, Syria, and Lebanon were under Byzantine control, for the first time since Heraclius in the 630s. By this time, however, John was sick, and he died on January 10, 976.