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The most widely confessed statement of Christian faith. Grown from the second-century baptismal creed of Rome and fixed in its present form by about the eighth century, its twelve articles follow the Trinity: Father, Son and Holy Spirit.
The Fourth Ecumenical Council's definition of Christ's person: truly God and truly man, in two natures "without confusion, without change, without division, without separation," united in one person. The boundary of orthodox Christology ever since.
The creed of the first ecumenical councils. Against Arius, Nicaea (325) confessed the Son "begotten, not made, of one substance with the Father"; Constantinople (381) expanded the article on the Holy Spirit. Shared by East and West.