When Alexios Komnenos seized power from the elderly Nikephoros III he was 24 years old. Alexios was a member of military aristocracy, and, despite his age, had already been a successful general under Michael VII and Nikephoros III. Alexios's reign marks the definitive victory of the military aristocracy, members of which would remain in power from now on. Alexios Komnenos was the first dynastic founder since Basil I two centuries earlier, and was the most successful emperor since Basil II. Unlike Basil, however, who harnessed the momentum of earlier emperors to bring the empire to its apogee, Alexios rebuilt the state after successive invasions, civil wars, and financial crisis. He did this not through great innovation, but through successful adaptation of the machinery of state to new social, political, and economic realities.
At Alexios's assumption of power in 1081 the empire had lost its Asian provinces, and the Turks of Smyrna were taking to the sea to raid the Aegean islands, even besieging Constantinople in 1090/91. Byzantine Italy had fallen to the Normans, who were planning an invasion of the Balkans, which were not fully under Byzantine control because of the incursions of Patzinaks and others from north of the Danube. By the time of Alexios's death in 1118, the Normans had been defeated twice (in 1085 and in 1108), the Patzinaks had been almost obliterated as a people in 1091, and the northwestern quarter of Asia Minor had been recovered from the Turks. In this last success much credit must be given to Alexios's clever use of the First Crusade that arrived in Byzantium in 1096.
After reaching the deepest point of debasement in the 1080s, Byzantine currency was reformed in 1092 with four denominations, three of which were alloyed. This proved adaptable for trade and, with the fiscal reforms of 1106–9, ensured the renewal of the imperial treasury. One act, which may have both stimulated the imperial economy and laid the foundations of future problems, was the granting of trade privileges to the Venetians. Alexios had done this to acquire Venetian aid against the Normans in the 1080s. While probably increasing the volume of international trade in Byzantium, eventually the tax exemptions granted to Italians would give them an advantage over Byzantine merchants and deny the state an important source of income.
Alexios also pioneered a new way of running the empire. The frequent rebellions that had plagued imperial politics since the death of Basil II proved that the emperor needed provincial governors, generals, admirals, and administrators that he could trust. Alexios turned to his family, and those linked to the Komnenoi by marriage or blood. By arranging clever marriages for his children and other family members, Alexios bound much of the aristocracy to his clan. Alexios was so successful at intertwining the ruling dynasty with other families of the military aristocracy that although four more families would sit the throne of Byzantium, as well as the rulers of the splinter states of Trebizond and Epiros, every emperor after him was his direct descendent.
The seals of Alexios reveal, perhaps unwittingly, extensive connections to past emperors. The obverse revives the enthroned Christ type of Constantine X and Michael VII, into whose family Alexios married. Komnenos, his family name, appears on the reverse inscription, a practice started by his uncle Isaakios I, and echoes the process of aristocratization that made family connections the highest qualification for state office. Alexios’s portrait, meanwhile, conserves the regalia of Nikephoros III, against whom Alexios rebelled after having served as his adviser.