ܐܦܛܪܘܦܘܬܐ ܦܛܪܝܪܟܝܬܐ
 ܕܡܪܥܝܬܐ ܕܐܘܚܕ̈ܢܐ ܡܥܪ̈ܒܝܐ ܕܐܡܝܪܟܐ

He was much praised by Jerome and Eusebius of Caesarea for his theological writings, and he was considered one of the chief theologians of his era. He became bishop of Antioch (191 - 211).

Eusebius refers to three works of Serapion in his history, but admits that others probably existed: first is a private letter addressed to Caricus and Pontius against Montanism, from which Eusebius quotes an extract (Ecclesiastical History V, 19), as well as ascriptions showing that it was circulated amongst bishops in Asia and Thrace; next is a work addressed to a certain Domninus, who in time of persecution abandoned Christianity for the error of "Jewish will-worship" (E. H., VI, 12); and lastly Eusebius quotes from a pamphlet Serapion wrote concerning the Docetic Gospel of Peter, in which Serapion presents an argument to the Christian community of Rhossus in Syria against the Gnostic message of this gospel, and also alludes to a number of personal letters Serapion wrote to Pontius, Caricus, and others about this Gnostic document.

Serapion also acted against the influence of Gnosticism in Osroene by consecrating Palut as bishop of Edessa, where Palut addressed the increasingly Gnostic tendencies that the churchman Bardesanes was introducing to its Christian community.

It is written in the Ecclesiastical History of the Patriarchs (By Y. Dolabani, Metropolitan of Mardin P. 12) "that the Christians of Persia, in any case, were originally subject to the Patriarch of Antioch. It was Serapion of Antioch who allowed their bishops to be ordained by their own suffragans" because of the bad situation between  Romans and Persian, and the great distance of the Church in Persia from Antioch led in early times to a state of semi-independence that prepared the way for the later schism. As to be the vicar of the Patriarch of Antioch, the metropolitan of the twin-cities of Seleucia and Ctesiphon (on either side of the Tigris, north-east of Babylon) bore the title of Catholicos. One of these metropolitans was present at the Council of Nicaea in 325.