MANUEL I., COMNENUS (c. Byzantine em peror (1143-1180), the fourth son of John II., was born about 1120. Having distinguished himself as a soldier, he was nominated emperor in preference to his elder surviving brother. He en deavoured to restore by force of arms the predominance of the Byzantine empire in the Mediterranean countries. In 1144 he brought back Raymond of Antioch to his allegiance, and in the following year drove the Turks out of Isauria. In 1147 he granted a passage through his dominions to two armies of crusaders under Conrad III. of Germany and Louis VII. of France ; but the num erous outbreaks of hostility between the Franks and the Greeks on their line of march, nearly precipitated a conflict between Manuel and his guests. In the same year the emperor made war upon Roger of Sicily, whose fleet captured Corfu and plundered the Greek towns, but in 1148 was defeated with the help of the Venetians. In 1149 Manuel recovered Corfu and prepared to take the offensive against the Normans. With an army mainly com posed of mercenary Italians he invaded Sicily and Apulia, and although defeated both on land and sea, Manuel maintained a foothold in southern Italy, which was secured to him by a peace in 1155.
Manuel made treaties with Pisa and Genoa, and supported the free Italian cities with his gold and negotiated with pope Alexander III. In spite of his friendliness towards the Roman church Manuel was refused the title of "Augustus" and he nowhere succeeded in attaching the Italians permanently to his interests. None the less in a war with the Venetians he actually drove his enemies out of the Aegean Sea. On his northern frontier Manuel defeated the rebellious Serbs (1150-52) and made re peated attacks upon the Hungarians. In the wars of 1151-53 and 1163-68 he led his troops into Hungary but failed to maintain himself there; in 1168, however, a decisive victory near Semlin enabled him to conclude a peace by which Dalmatia and other frontier strips were ceded to him. In 1169 he sent a joint expedi
tion with King Amalric of Jerusalem to Egypt, which retired after an ineffectual attempt to capture Damietta. In 1158-59 he fought with success against Raymond of Antioch and the Turks of Iconium. In 1176 he was decisively beaten by them in the pass of Myriokephalon. This disaster, though partly retrieved in the campaign of the following year, had a serious effect upon his vitality ; henceforth he declined in health and in II80 succumbed to a slow fever.
In spite of his military prowess Manuel achieved but in a slight degree his object of restoring the East Roman empire. His vic tories were counterbalanced by numerous defeats, and his lack of statesmanlike talent prevented his securing the loyalty of his subjects. The expense of keeping up his mercenary establishment put a severe strain upon the financial resources of the state. The subsequent rapid collapse of the Byzantine empire was largely due to his brilliant but unproductive reign. Manuel married, firstly, a sister-in-law of Conrad III. of Germany ; and secondly, a daughter of Raymond of Antioch. His successor, Alexis II., was a son of the latter.
See John Cinnamus, History of John and Manuel (ed. 1836, Bonn) ; E. Gibbon, The Decline and Fall of the Roman Empire (ed. Bury, London, 1896), V. 229 sqq., vi. 214 sqq.; G. Finlay, History of Greece (ed. 1877, Oxford), iii. 143-197; H. v. Kap-Herr, Die abendldndische Politik Kaiser Manuels (Strassburg, i881). (M. C.)