ARSACIUS, St. — Confessor, died c. 358 at Nicomedia. According to Sozomen (Hist. ecc., IV, 16), he was of Persian birth, confessed the faith under Licinius, and after serving for some time in the imperial palace retired to an eremitical life at Nicomedia, where he died as a victim of the earthquake, which he had foretold, that destroyed the city on 24 Aug. 358. In the Middle Ages the cult of St. Arsacius was known at Naples, Milan, and Bavaria. Later legends made him a disciple and successor of St. Ambrose, or a brother of St. Eustorgius II, archbishop of Milan. The Roman Martyrology commemorates him on 16 Aug.
BIBL.: Martyrologium Romanum, p. 343; Acta SS. Augusti, III, Paris 1867, pp. 270-73; G. Ratzinger, Der hl. Arastius von Illmünster, in Theol. prakt. Monatschrift, 2 (1892), p. 493 ff. Mario Scaduto