Synod of Alexandria, (362 ce), a meeting of Christian bishops held in Alexandria, Egypt, summoned by the bishop of Alexandria, St. Athanasius, in an appeal for unity among those who held the same faith but differed in terminology. The synod allowed clergy who had been readmitted to communion after making common cause with Arians to return to their former ecclesiastical status, provided they had not themselves subscribed to Arianism. The synod stated explicitly that the Holy Spirit is not a created being and is of the same substance (“consubstantial”) as the Father and the Son. It also clearly defined the Christological terms person and substance, thus preparing for the orthodox doctrine of the Trinity as “three persons in one substance.”
Several other councils and synods were held at Alexandria, including one in 363 that was also called by Athanasius.