The First Council of Nicaea was a council of Christian bishops convened in the Bithynian city of Nicaea by the Roman Emperor Constantine I in AD 325. This first ecumenical council was the first effort to attain consensus in the church through an assembly representing all of Christendom, although previous councils, including the first Church council, the Council of Jerusalem, had met before to settle matters of dispute. It was presided over by Hosius, bishop of Corduba. Its main accomplishments were settlement of the Christological issue of the nature of the Son of God and his relationship to God the Father, the construction of the first part of the Creed of Nicaea, establishing uniform observance of the date of Easter,and promulgation of early canon law.
The First Council of Nicaea was the first ecumenical council of the Church. Most significantly, it resulted in the first uniform Christian doctrine, called the Nicene Creed. With the creation of the creed, a precedent was established for subsequent local and regional councils of Bishops (Synods) to create statements of belief and canons of doctrinal orthodoxy—the intent being to define unity of beliefs for the whole of Christendom.
One purpose of the council was to resolve disagreements arising from within the Church of Alexandria over the nature of the Son in his relationship to the Father: in particular, whether the Son had been 'begotten' by the Father from his own being, and therefore having no beginning, or else created out of nothing, and therefore having a beginning. St. Alexander of Alexandria and Athanasius took the first position; the popular presbyter Arius, from whom the term Arianism comes, took the second. The council decided against the Arians overwhelmingly (of the estimated 250–318 attendees, all but two agreed to sign the creed and these two, along with Arius, were banished to Illyria).
Another result of the council was an agreement on when to celebrate Easter, the most important feast of the ecclesiastical calendar, decreed in an epistle to the Church of Alexandria in which is simply stated:
Historically significant as the first effort to attain consensus in the church through an assembly representing all of Christendom, the Council was the first occasion where the technical aspects of Christology were discussed. Through it a precedent was set for subsequent general councils to adopt creeds and canons. This council is generally considered the beginning of the period of the First seven Ecumenical Councils in the History of Christianity.
The First Council of Nicaea was convened by Emperor Constantine the Great upon the recommendations of a synod led by Hosius of Córdoba in the Eastertide of 325. This synod had been charged with investigation of the trouble brought about by the Arian controversy in the Greek-speaking east. To most bishops, the teachings of Arius were heretical and dangerous to the salvation of souls.
In the summer of 325, the bishops of all provinces were summoned to Nicaea.
This was the first general council in the history of the Church since the Apostolic Council of Jerusalem, the Apostolic council having established the conditions upon which Gentiles could join the Church
The agenda of the synod included:
- The Arian question regarding the relationship between God the Father and the Son (not only in his incarnate form as Jesus, but also in his nature before the creation of the world); i.e., are the Father and Son one in divine purpose only or also one in being?
- The date of celebration of Pascha/Easter
- The Meletian schism
- Various matters of church discipline, which resulted in twenty canons
- Church structures: focused on the ordering of the episcopacy
- Dignity of the clergy: issues of ordination at all levels and of suitability of behavior and background for clergy
- Reconciliation of the lapsed: establishing norms for public repentance and penance
- Readmission to the Church of heretics and schismatics: including issues of when reordination and/or rebaptism were to be required
- Liturgical practice: including the place of deacons, and the practice of standing at prayer during liturgy
Contrary to the claims of some fringe authors and cults, the council did not address any questions regarding the canon of scripture.
The council promulgated twenty new church laws, called canons, that is, unchanging rules of discipline. The twenty as listed in the Nicene and Post-Nicene Fathers are as follows:
- 1. prohibition of self-castration
- 2. establishment of a minimum term for catechumens (persons studying for baptism)
- 3. prohibition of the presence in the house of a cleric of a younger woman who might bring him under suspicion
- 4. ordination of a bishop in the presence of at least three provincial bishops and confirmation by the metropolitan bishop
- 5. provision for two provincial synods to be held annually
- 6. exceptional authority acknowledged for the patriarchs of Alexandria (pope), Antioch, and Rome (the Pope), for their respective regions
- 7. recognition of the honorary rights of the see of Jerusalem
- 8. provision for agreement with the Novatianists, an early sect
- 9–14. provision for mild procedure against the lapsed during the persecution under Licinius
- 15–16. prohibition of the removal of priests
- 17. prohibition of usury among the clergy
- 18. precedence of bishops and presbyters before deacons in receiving the Eucharist (Holy Communion)
- 19. declaration of the invalidity of baptism by Paulian heretics
- 20. prohibition of kneeling on Sundays and during the Pentecost (the fifty days commencing on Easter). Standing was the normative posture for prayer at this time, as it still is among the Eastern Christians. Kneeling was considered most appropriate to penitential prayer, as distinct from the festive nature of Eastertide and its remembrance every Sunday. The canon itself was designed only to ensure uniformity of practice at the designated times.