The Council of Nicaea (325 A.D.), gave us the Nicene Creed which we proclaim every Sunday at Mass. This Council taught that Jesus was consubstantial with God, one in being with the Father. In that prayer, we proclaim Jesus as "the only-begotten Son of God, eternally begotten of the Father, light from light, true God from true God, begotten not made, one in Being (consubstantial) with the Father."

Towards the end of the same century (381 A.D.), we were taught "We believe in the Holy Spirit, the Lord and giver of life, who proceeds from the Father and the Son."_

These few examples we've stated are not by any means all the teachings about our belief in the Trinity. They are just the tip of the iceberg. Woven throughout the history of the Church, as well as the teachings of the Church, we find references about the Trinity. The ones we've mentioned are the most obvious, to which the lay community is exposed on a daily basis, whenever we make the Sign of the Cross.

Even before the Council of Nicaea (325 A.D.) which was the first Ecumenical Council, teachings on the Trinity were given us by the Early Fathers of the Church.