The three-penny Catechism of Christian Doctrine (1958 edition) has two questions, 29 and 30, on ‘the likeness to the Blessed Trinity in the soul’. They state that ‘there is this likeness to the Blessed Trinity in my soul; that as in one God there are three Persons, so in my one soul there are three powers. The three powers of my soul are my memory, niy understanding and my will’. This is an echo, but a seriously distorted one, of Augustine's teaching about the image in the De Trinitate, especially in books ix and x, which we will be examining in this article. The distortion is curiously ancient, not to say inveterate; it is to be found in the Sentences of Peter Lombard, the twelfth century work which was to remain the standard theological text-book of the schools of the sixteenth century and beyond, and although it was explicitly corrected by St Thomas, here it is, as brazen as ever, in the catechism of the twentieth century.