"The mystery of the Most Holy Trinity is the central mystery of Christian ... came to recognize and receive the Symbol of 381. The use of this formula in the Creed was gradually admitted into ...

The doctrine of the Trinity identifies the Holy Spirit as the third person in the Godhead. This teaching was established at ...

The feast of the Holy Trinity, which is celebrated on the Sunday after Pentecost, was established for the whole Western Church in 1134 by pope John XII. The Angelic Trisagion is said for the three ...