Patriarch of Constantinople, in the thirteenth century; died 1273. He entered a monastery in Nicæa, changing his secular name George for Gennadius and finally for Arsenius, and became the hegoumenos (abbot) of the monastery without taking orders. On his return from an embassy to Pope Innocent IV from John III Vatatzes in 1254, he withdrew to a monastery on Lake Apollonias in Bithynia. Hither the envoys of Theodore II Lascaris, who had succeeded Vatatzes in 1255, came to offer him the patriarchal throne, made vacant in 1254 by the death of Manuel. His patriarchate was peacefu1 till the rise of Michael Palaeologus. Theodore II died in 1258, entrusting his son John's minority to George Mouzalon, whom Michael murdered and supplanted. Vainly remonstrating, Arsenius withdrew to the monastery of Paschasius without resigning his authority. Failing to make him either act or resign, the emperor and the court bishops replaced him by Nicephorus of Ephesus, who died after six months. The recovery of Constantinople by the Greeks in July, 1261, rendered the choice of a patriarch imperative. His partisans renominated Arsenius, whom the emperor accepted, provided he recognized the validity of the orders conferred by Nicephorus. Arsenius agreed but refused to officiate with the new bishops. On his return he crowned Michael for the second time in St. Sophia, reserving intact, as he imagined, the rights of John. To make sure, however, that John should never succeed him, Michael destroyed his ward's eyes, 25 Dec., 1261. Shocked at this atrocity, the patriarch excommunicated him and demanded his absolute abandonment of the imperial throne. Michael refused, and after two years' contention deposed Arsenius (May, 1264) and exiled him to the convent of St. Nicholas on the island of Proconnesus, where he died. The adherents of Arsenius, including the emperor's own kinsmen, withdrew from the communion of the new patriarch, Germanus, formerly Bishop of Adrianople. The next patriarch undertook, in 1267, to absolve the emperor from the sentence of excommunication imposed by Arsenius. This gave rise to the Arsenian schism, which lasted until April, 1315, when it finally yielded to the diplomacy of the Patriarch Niphon.
PETIT in Dictionnaire de théologie catholique (Paris, 1902) s. v. Arsène Autorianus; NATALIS; ALEXANDER, Hist. Eccl. (Venice, 1771), XVI, viii, art. 3; 4.
MARK J. MCNEAL