By St. Nikodemos the Hagiorite
Various synods, or rather to say conventions, of the Holy Apostles, according to some, were held as follows.
The first one in the year 33 or 34 after the Nativity of Christ, with regard to the selection of an apostle to take the place of Judas the traitor, when, after Joseph and Matthias were proposed, the lot fell to Matthias (Acts 1).
The second was held in connection with believers whose heart and soul were one, when all of them who owned fields and houses, or anything else, would sell them and bring the money and lay it at the feet of the Apostles, in order that they might provide for those who were in want (Acts 4:4). Admittedly, however, this convention cannot be plainly inferred from the text of the Acts.
The third one was held when the deacons were selected to serve at table (Acts 6:2).
The fourth, when the Apostles and the brethren by circumcision heard that St. Peter had baptized the heathen Cornelius with all his household, and began quarreling with him (Acts 11:2-8).
The fifth one was held when the Apostles and the priests (or elders) assembled themselves to consider the question as to whether those faithful who had not been circumcised in accordance with the law of Moses could not be saved, as some persons were saying who had come down from Judea to Antioch. This convention and synod proper of the Apostles is one which every critic must call a synod, or rather to say, an example and prototype of later synods, since it contains also the name and the characteristic peculiarities of synods.
“For there rose up certain men among the sect of the Pharisees, saying that it was necessary to circumcise them” (Acts 15:5).
Here, behold, is the dispute and quarrel which the synod required: “and the apostles and elders convened to consider this matter” (Acts 15:6) (here, behold, the synod is even called a convention); “and after there had been much discussion” (Acts 15:7) (here, behold, was the preceding investigation concerning it); “then it seemed best to the apostles and the elders together with all the church” (Acts 15:22). And “it seemed best to the Holy Spirit and to us” (Acts 15:28) (here, behold, are to be seen the vote and the decision). This convention took place after the Ascension of Christ in the year 37.
The sixth convention of the Apostles took place in the year 56 or 58, when St. Paul went in with them to James, the brother of God: “and all the elders were present” (Acts 21:18).
Some authors think that there was also another convention of the Apostles in Antioch, which promulgated nine canons, as is noted by several Western Fathers (concerning which see the footnote to Apostolic Canon 85), and even other conventions, of which the largest and notable one, say the Westerners, was held in the year 34, when the Apostles were about to separate from each other. There it was, they say, that the Symbol of the Faith called the Creed of the Holy Apostles was composed (concerning which see the second footnote to Canon I of the Sixth). These things being as stated, at which one of these conventions did the divine Apostles issue through Clement the present 85 Canons of theirs? Regarding this point antiquity has left us no exact information stochastically. Nevertheless, one might say that they ordained them at that said largest and notable convention, when they were about to separate from each other and to be scattered for the preaching of the Gospel.
From The Rudder, "Prologue Concerning the Canons of the Holy Apostles".