other · 180 · Antioch
Autolycus was a pagan of some learning who wanted to be shown a God he could see. Theophilus answers that the instrument has to be fit before it can receive: show me thy man, he says, and I will show thee my God — meaning that a clouded eye cannot see the sun and it is not the sun's fault. From there he argues creation against the eternity of matter, sets the biblical chronology against the Greek historians, and in the second book uses the word trias, triad, of God, his Word and his Wisdom. It is the earliest surviving use of the term that became Trinity, and it is made in passing, in an argument about the three days before the luminaries. Eusebius catalogues the three books together with another writing entitled Against the Heresy of Hermogenes, in which he says Theophilus makes use of testimonies from the Apocalypse of John — an early external witness to that book, and lost.
To answer a cultivated friend who had said, in effect, produce your God and I will believe in him.
Three books that survive, a lost one against Hermogenes, and the first surviving use of the word Trinity for God.