He was a friend of Pope Gregory I, and aroused the enmity of the Emperor Justinian by opposing certain imperial doctrines about the Body of Christ (Justinian favoured the Aphthartodocetae). He was to be deposed from his See and exiled when Justinian died; but Justin II carried out his uncle's purpose five years later in 570, and another bishop, Gregory of Antioch, was put in his place. But when Gregory died in 593, Anastasius was restored to his See. This was chiefly due to Pope Gregory the Great, who interceded with the Emperor Maurice and his son Theodosius, asking that Anastasius be sent to Rome, if not reinstated at Antioch. He was killed by a Jewish mob in 599. His feast day is 21 April.
From some letters sent to him by Gregory, it is thought that he was not sufficiently vigorous in denouncing the claims of the Patriarch of Constantinople to be a universal bishop. Anastasius died in 598, and another bishop of the same name is said to have succeeded him in 599, to whom the translation Gregory's Regula Pastoralis is attributed, and who is recorded as having been put to death in an insurrection of the Jews. Nicephorus (Hist. Eccl., XVIII, xliv) declares that these two are one and the same person. The same difficulty occurs with regard to certain Sermones de orthodoxâ fide, some ascribing them to the latter Anastasius; others claiming that there was but one bishop of that name.