ARSENIUS AUTORIANUS. – Born in Constantinople at the beginning of the 13th century, he changed his name from George to A. when he entered the monastery of Oxia near Nicaea, where he became hegumen. He acceded to all the wishes of Emperor Theodore II Lascaris, who had elected him Patriarch of Constantinople (1254). When Michael Palaeologus seized power in 1258, A. threatened him, abandoned the patriarchal see, and agreed to return only on condition that he would do so after the death of his successor, Nicephorus of Ephesus. He crowned Michael in Hagia Sophia, but when Palaeologus in 1261 allowed John Lascaris, son of the deceased emperor and ward of the patriarch, to accede, A. excommunicated him. The emperor had him deposed, and he died on the island of Proconnesus in 1273, leaving behind him a serious schism.
Works: 1) Testament: a historical document of the time, PG 140, 947-58. 2) Bulls. 3) Part of the ritual for the Unction: ibid., 808. 4) An unpublished treatise contained in ms. 7 Lincoln, Oxford. He is wrongly attributed with a Synopsis Canonum written in 1255 by another A., a monk of Mount Athos.