Manuel I Comnenus (ca. 1123-1180) was Byzantine emperor from 1143 to 1180. Although he was a talented ruler, his diplomatic and military over-extensions left his realm dangerously isolated and humiliated.
The fourth son of John II Comnenus (1118-1143), Manuel was the second one surviving at the time of his father's death in a "hunting accident" that was probably an assassination. Supposedly by the dying John's wish, Manuel was given the throne in preference to his older brother. Manuel assembled a dazzling and lavish court and presided over one of the most brilliant phases of Byzantine culture. He was also an able soldier, strategist, and commander. Nevertheless, his perception seems to have been at times superficial, and his policies, although imaginative, were often misguided.
Manuel's basic policies were to recover the lands in Asia Minor lost to the Turks, to assert control over the crusader states of the Holy Land, to maintain domination of the sub-Danubian Balkans, to recover Byzantine rights and lands in Italy, and to restore the empire's international position.
At the outset of his reign, Manuel built his diplomatic hopes on cooperation with the new Hohenstaufen dynasty of Germany, planning thereby to check the aggressive Norman king of Sicily and southern Italy, Roger II. The alliance was sealed by Manuel's marriage to Bertha of Sulzbach, sister-in-law of the German emperor Conrad III. But this entente was badly disrupted by Conrad's participation in the abortive Second Crusade (1147-1149). Freed from German pressure, Roger sent his fleets to devastate Byzantine Greece ruthlessly. Conrad renewed his alliance with Manuel, but he died soon after his return. He left the German throne to his nephew Frederick I Barbarossa, who soon ended any illusions of continued Comnenian-Hohenstaufen cooperation.
Manuel's other initial ally, and his supporter in his continuing wars with Roger, was Venice. But ill feelings developed between Manuel and Venice, so the Emperor endeavored to play off Venice and the other major Italian maritime powers, Genoa and Pisa, against each other. He also cultivated the papacy, especially under Frederick's enemy, Alexander III, in the vain hope of ending the schism of the Churches and of being recognized as emperor of both East and West. Further, he supported the north Italian cities in their struggles against Frederick. Manuel's Italian interests were not merely diplomatic, however, for he sought to restore in the peninsula the power of the Byzantines, expelled since the Norman conquest of the south a century earlier. He therefore occupied Ancona in 1151 and endeavored to annex the entire eastern coast; but reverses followed, and by 1158 these footholds were finally lost. Meanwhile, Manuel's relations with Venice deteriorated so badly that in 1171 the Emperor ordered all Venetians within the empire arrested and their properties confiscated. This led to new hostilities.
In other spheres, Manuel achieved clearer success. In the Balkans, during the 1150s and 1160s, Manuel effectively resisted the ambitions of Hungary and established the most comprehensive control of the sub-Danubian regions that the empire had enjoyed since the 6th century. Likewise successful was his domination of the Armenians of Cilicia and, especially, the Latins of the crusader states. The climax of this effort was his triumphant reception in Antioch in 1159, where both that city's prince and the king of Jerusalem acknowledged his suzerainty.
Yet, it was in the East that Manuel's ultimate humiliation came. His strategic blunders as commander delivered his army to a dreadful massacre by the Turks in 1176, at Myriokephalon, from which Manuel himself fled for his life. This disaster sealed forever the Byzantine loss of central Asia Minor. This humiliation also capped the destruction of his international image; he was reduced to insignificance beside the prestigious Frederick Barbarossa.
Likewise in his domestic regime, Manuel was imaginative but not consistently successful. His ecclesiastical policies were firm and constructive, aimed at curbing excessive monastic wealth. The empire's economy also flourished to a considerable extent, but its effects were qualified by Manuel's lavish expenditures and heavy taxation. He found it impossible to check the progress of quasi-feudal power and independence among the powerful landed aristocrats, and his efforts at cultivating or encouraging other orders of society were ill-timed. He made free and open-minded use of Westerners and other peoples, but his cosmopolitanism was out of tune with the increasingly narrow Hellenism of his people, and it antagonized them. The Emperor died on Sept. 24, 1180.
The basic study of the Comneni is in French. Lively sketches of Manuel's two Latin wives are in Joseph McCabe, The Empresses of Constantinople (1913), and Charles Diehl, Byzantine Empresses (1963). A general account of the reign is in The Cambridge Medieval History, vol. 4 (1923; 2d ed., 2 pts., 1966), and George Ostrogorsky, History of the Byzantine State (1956; rev. ed. 1969). Andrew B. Urbansky, Byzantium and the Danube Frontier (1968), is a study of the relations between Byzantium, Hungary, and the Balkan states during the period of the Comneni.