the Athanasian Creed, a statement of faith from the fifth or sixth century, which begins: “Whosoever will be saved, before all things it is necessary that he hold the catholic [that is, the church’s orthodox] faith; which faith except every one do keep whole and undefiled, without doubt he shall perish everlastingly. And the catholic faith is this: that we worship one God in Trinity, and Trinity in Unity.”