Why celebrate the 1,700th anniversary of the Council of Nicaea so solemnly in the year 2025? Because the meeting of bishops convened by Constantine affirmed the divinity of the Son in the face of Arian heresies. Because the fathers drew up a creed that is still in force today. And, because the event was also the first ecumenical council, in the sense of a gathering of all the parts of the Church of the time.
This does not mean that Nicaea I, to distinguish it from Nicaea II, the second ecumenical council held in Nicaea in 787 to resolve the iconoclast question, is the first council.
The originality of this council of 325 comes from several factors. First, it was convoked not by a bishop or pope, but by the emperor Constantine, who was concerned about the unity of his empire, which was being torn by a theological argument. Second, the council resolved this issue through the production of a dogmatic definition and the proclamation of a creed.
But above all, this council stood out from previous ones because of the diversity of the people present, from representatives of the Pope of Rome to the bishops of the East. Because, to tell the truth, there were many councils before Nicaea. A council is in fact only a meeting of bishops, which can be local, to settle a problem of faith or discipline.
Numerous particular councils
In this context, the first known council seems to be the Council of Jerusalem, described by St. Paul in his epistle to the Galatians. Written around 50 or 51, this letter describes the assembly of apostles and elders (presbyters) which had been held some time earlier under the aegis of James, first bishop of the Holy City. The issue that brought them together was simple: Did one have to be Jewish (and therefore circumcised) to become a Christian? We know their conclusion.
Many other regional councils were held before 325 (and after): in Carthage, in 251, where there were heated debates on the return of former apostates; in Rome, to condemn modalism; then in Antioch (264); in Elvira in Spain in 305, concerning the marriage of Christians and the celibacy of clerics; and in Arles in 314 regarding Donatism. This is just a sample; there were f14 known councils in the period 251-325 alone.
The originality of Nicaea is therefore the fact that it was “ecumenical” — “universal” (from the Greek “entire inhabited earth”) — in terms of its participants and its reception. In fact, this adjective was only added by posterity in view of the teachings of the council.
The Orthodox today recognize seven ecumenical councils (up to 787, Nicaea II), the Protestants generally six (up to 681, Constantinople III) and the Catholic Church 21 (up to 1965, Vatican II).
