Every Sunday we say or sing at mass a text first formulated in 325 at the First Council of Nicaea, in a slightly expanded form adopted at the First Council of Constantinople in 381. I encapsulates central truths of the Christian gospel, which were much debated at the time. The first and most basic clause of that ancient text is “I believe in one God.” The rest of the creed is concerned with Our Lord and his Church, but this first article goes behind all that, to the source of everything and everyone.