EUSTATHIUS (d. c. archbishop of Thessalonica, Byzantine scholar and author (probably a native of Constanti nople), was bishop of Myra in Lycia, before being transferred to Thessalonica in 1175. He opposed the emperor Manuel, when the latter desired an alteration in the formula of abjuration necessary for converts from Mohammedanism, and in 1185, when Thessalonica was captured by William II. of Sicily, secured religious toleration for the conquered. His best known work is his Cotnmentary on the Iliad and Odyssey of Homer, which contains valuable extracts from the scholia of other critics, whose works are lost. The commentary on the geographical epic of Dionysius Periegetes also preserves much of Stephanus of Byzantium and the lost writings of Arrian. Of his commentary on Pindar only the preface, which contains an essay on lyric poetry, a life of Pindar and an account of the Olympic games, remains. Eustathius also wrote a history of the conquest of Thessalonica by the Normans, and The Reform of Monastic Life.
Editions: Homer Commentary, by G. Stallbaum (1825-3o) ; preface to Pindar Commentary, by F. W. Schneidewin (1837) ; Dionysius Commentary in C. W. Muller, Geographici Graeci minores, ii.; pente costal hymn, in A. Mai, Spicilegium Romanum, v. 2 (1841) . The smaller works and the De Thessalonica were edited (1832 and by L. F. Tafel; many will be found in Migne, Patrol. Graeca, cxxxv., cxxxvi. Five new speeches have been edited by W. Regel, Fontes rerum Byzantinarum, i. (1892) . See J. E. Kalitsunakis, Mittel- and Neu griechische Erklarungen bei Eustathius (1919) .