Roman Empire still remained potent, it was redefined and in many parts of the Mediterranean the power of the old empires--Byzantine, Carolingian, and Muslim--had been replaced by smaller, localized states, some of them only the size of cities. Centralized authority had become eroded and the bonds which held distant territories together were more often those of religion and cultural tradition than of a single political authority.
Nowhere was this more true than in what has aptly been termed the 'Byzantine Commonwealth': territories either under the authority of Constantinople or within its powerful cultural orbit. In the three hundred years after 900 the armies of the empire expanded its frontiers to their widest extent since the sixth century but then proved unable to maintain their supremacy against new and unexpected outside threats. The tenth century was the great age of expansion and reconquest. There were three main areas where this was most noticeable: the eastern frontier, Italy, and parts of the Balkans. In the east, stratēgoi (military governors) are found in Charsianon in 873, in Sebastea in 911, in Lycandus (east of Caesarea/Kayseri) by 916, and Tephrike (to the west of the upper reaches of the Euphrates) between 934 and 944. By the end of the century they are mentioned in such areas as Tarsus, Theodosiopolis (modern Erzerum), and the Taron region of Armenia to the north-east of Lake Van. In Italy, the existence of the stratēgoi of Langobardia (by 911) and Calabria (c. 948-52) testifies to a re-establishment of Byzantine power in southern Italy, which culminated in the reign of the Emperor Nicephorus II Phocas ( 963-9), who created a new post of katepan of Italy to oversee the administration of all Byzantine territories there. In the Balkans, the establishment of such themes (administrative districts) as Strymon and Nicopolis (northern Greece) and Dalmatia at the end of the ninth century marked the revival of Byzantine authority in lands which had previously fallen to Slav and Avar attack. More were added after the successful conquest of Bulgaria by Basil II at the beginning of the eleventh century.
The means by which these successes were achieved them-
-167-