On this day 325 AD:
The Council of Nicaea, the first ecumenical debate held by the early Christian church, concluded with the establishment of the Holy Trinity and the adoption of the first uniform Christian doctrine known as the Nicene Creed.
As the early Christian church grew in the Roman empire it was also beset by so many crises. The most controversial emerged when Arius, an Alexandrian priest, questioned the full divinity of Christ arguing that, unlike God, Christ was born and had a beginning.
Many Bishops perceived the teachings of Arius as heretical and dangerous to the salvation of souls. What began as an academic theological debate spread to Christian congregations throughout the empire, threatening a schism in the early Christian church.
In May 325 AD, Roman Emperor Constantine I, who converted to Christianity in 312, convened a meeting of all Bishops across his empire at Nicaea (in present-day Turkey) to resolve the crisis and urged the adoption of a new creed that would settle the ambiguities between Christ and God.
On August 25, 325 AD, after marathon deliberations, an estimated 318 Bishops, agreed on the equality of the Father, the Son, and the Holy Spirit in the Holy Trinity and asserted that only the Son became incarnate as Jesus Christ.
The Arian leaders were subsequently excommunicated and banished into exile and the Nicene Creed was adopted as the unified statement of belief widely used in Christian liturgy till date.