Byzantine calls to the west for help against the Seljuks in the wake of Manzikert had contributed to the calling of the First Crusade. However, the crusading movement as a whole did little to advance the interests of Byzantium in the twelfth century, and relations between the two sets of Christian states were often unfriendly. Nevertheless, between 1081 and 1180, the Comneni emperors Alexius, John, and Manuel managed to rebuild a good deal of Byzantium’s power and prestige. Alexius secured almost all the empire’s European territory and some of the coast of Asia Minor; John and Manuel gradually took more of the coast, and Manuel, through friendly relations with Jerusalem, exerted influence in the Crusader States. Byzantine trade wealth remained substantial, and the agricultural base of the empire in the Balkans was strong. Byzantine success in this century was based on wealth, diplomacy and the prestige of the empire, backed by a military system rebuilt by the Comneni along very different lines from the old Byzantine army.
The disaster at Manzikert and the subsequent loss of Anatolia had been the death knell for the already declining thematic army, and almost all the tagmata units had also ceased to exist in the ten years of civil war after Manzikert (see Chapter 8). Thus, the Comnenian military system, while drawing on the strategic and tactical wisdom contained in the treatises of the earlier age, had almost no institutional continuity with the pre-1025 army. It depended on two main sources of manpower. First, there were the remaining military aristocrats and their followers. But this source was limited by the Comnenian policy, most clearly under Manuel, of concentrating land and power in the hands of the royal family—a reaction to the civil wars and dissension that had led to disaster in the first place. So, while this source provided a cadre of leadership, it could not supply the manpower for major armies. The second source of manpower, foreign mercenaries, made up the bulk of Byzantine forces in this period. Such soldiers ranged from western Latin knights to Petchenegs and other Asiatic horsemen. This heterogeneous force perhaps lacked the common tactical doctrine of the old Byzantine army, but it was capable of responding flexibly to a wide range of challenges and avoided the political dangers of the old system by remaining loyal to the emperor who hired it.
Both sources were supported increasingly not by direct payments from the treasury but by pronoia—a grant of the income (or a share of the income) from a piece of land. It was similar to the Muslim iqta, though it carried less in the way of administrative duties; it also had few of the implications of lordship carried by Latin fiefs. It was thus more purely a fiscal measure, representing an adaptive response by the Comneni to the changing economic base of the empire. There was no connection between the soldiers and their pronoia lands, and the foreignness of most pronoia recipients slowly became a source of unrest among the population. A gulf opened between the Byzantine military system and the social structure on which it was based, a development that made the empire more closely resemble Muslim states, where socially marginal nomads and iqta3 holders dominated a civilian population.
This Byzantine army, backed by the government’s wealth and led energetically and creatively by the early Comneni emperors, performed well for almost a century. By 1176, Manuel was strong enough to contemplate the reconquest of Anatolia from the Seljuk sultanate. If Manuel had been successful—and there was no reason inherent in the situation at the time that he could not have been—the subsequent course of history in the region would have been very different. But chance intervened, and the attempt ended in disaster. On September 17, Kilij Arslan’s Turkish army ambushed Manuel’s huge invading force in a pass near Myriocephalum and annihilated it; the emperor himself barely escaped. This “second Manzikert” sealed the possession of Anatolia by the Turks, did severe damage to Byzantine strength, and so freed Saladin in Syria to focus on the Crusader States exclusively. Four years later, Manuel died, and the traditional Achilles heel of Byzantium, succession problems, prevented any recovery. Byzantium turned away from Manuel’s policy of cooperation with the Crusader States. The Fourth Crusade in 1204 became entangled in Byzantine politics, opening an opportunity for western intervention and the venting of growing anti-Greek hostility in western Europe. The crusaders ended up taking and sacking Constantinople and dividing the empire.
The Fourth Crusade represented the end of Byzantium as a significant military power. The Greeks retook Constantinople in 1261, and the late Byzantine army retained some key administrative elements of the Comnenian period, including the pronoia system. But Turks and Mongols were the significant military players in the area, and in 1453, the Ottoman Turks extinguished the last territorial remnant of the empire by taking Constantinople. Byzantine culture lived on, though, and its influence spread, both to Russia and to Renaissance Italy, despite—or perhaps because of—the state’s decline and eventual disappearance.