Achigian, Andrew, an Asiatic Monophysite sectary who induced a party of his sect to forsake their religion for a time and unite themselves with the Romanists. He had been educated at Rome. and was appointed patriarch of Antioch by the Roman pontiff. He assumed the title of Ignatius XXIV. See Mosheim, Hist. of the Church, bk. 4 cent. 17 pt. 1, ch. 2, § 2.