Augustine's long exposition of the doctrine of theTrinity was written after the Council of Constantinople (381) had settled the matter of the consubstantiality of the three Persons of the Trinity. Augustine began this work around the year 400 and completed it in 416. Taking the image of God in the human being (Genesis 1:26-27) as his starting-point, Augustine reasons that since God is triune, the image must be so, too. There ensues a laborious quest for three aspects of every individual human being that serve as a mirror of the Trinity. En route to the successful outcome of his quest, Augustine explores a variety of theological and anthropological concepts.