Syr. Orth. patr. of Antioch, theologian, and liturgist, date of birth unknown but said to be a ‘young man’ (= under 40) at the time of his consecration in 580/1 and hence born ca. 550 (?), d. 22 April 591. A native of Kallinikos (Latin Callinicum; Arabic al-Raqqaʿ) he had probably been a monk (plausibly at the nearby monastery of Mar Ḥanino where he was consecrated) before election to a see troubled by problems of succession and with more than one claimant to canonical occupancy of the throne. Twice he refused the office even though pressed by Yaʿqub Burdʿoyo but yielded, probably unwillingly, to pressure. Certainly his first official act was to visit his fellow-Syrian and co-religionist Damian, Pope of Alexandria (577/8–606/7) avowedly to offer his resignation if that would unite the quarrelling parties; for Damian, a vigorous and effective reformer, was the acknowledged leader in the partnership of Syrian and Egyptian Churches. The offer, if made, was refused and the death of one of the claimants resolved a difficulty. The visit to Alexandria unintentionally occasioned the conversion to the ‘synodite’, i.e., Chalcedonian cause of two accompanying expert theologians, Proba and Yuḥanon Barbur, who were to be duly condemned by a synod (584/585) at Peter’s probable residence (he was banned from entry into Antioch) of the monastery of Gubba Barraya. Peter wrote against them, but the work has not survived. Relations between Pope and Patriarch, at the outset warm apparently, became strained following the publication by Damian in ca. 585 of a defence of the unity of God in Trinity against the teaching of John Philoponus and others; they finally broke down and a schism between the Churches of Syria and Egypt was mended only in 616 after the death of both disputants. Peter’s extant literary legacy consists of: 1. an Anaphora in Syriac (ed. R. Y.  Ebied and L. R.  Wickham, in Harp 23 [2008], 309–43); 2. A mimro ‘On the Crucifixion’; 3. parts of seven Letters (see R. Y. Ebied, A. Van Roey and L. R. Wickham, in OLA 10 [1981]); and 4. works in connexion with the tritheist controversy: a. Rebuttal of those charged with Sabellianism (= Pope Damian and the ‘Damianites’) and who therefore spread the libellous report about us of holding the heathen dogmas of the Tritheists; b. a treatise originally in three books of which the second survives in part and the third complete; unnamed in the mss. it has been given the title Against Damian by its recent editors. Quite probably (a) is in fact the remains of the lost first book of the treatise. The genuineness of 3 and 4 (all in early and excellent Syriac translation from the Greek) is guaranteed by the general witness of Michael Rabo; there is no reason to doubt Peter’s direct authorship of 2 and at least indirect of 1. The big treatise was valued for its extensive quotations from the Greek Fathers, extant florilegia being compiled from it and attesting the continuity and vigour of the Greek/W.-Syr. theological heritage.