Augustine began writing commentary on scripture not long after his conversion. His first such work, meant as a counterblast to Manichaean attacks on the creation account, was De Genesi contra Manichaeos (388-390). In many ways it sets the tone for much of his later work: Augustine admits an allegorical sense but warns against overenthusiasm for allegory and denigration of the literal sense; we see also from the outset Augustine's interest in scripture as a controversialist and polemicist. After his ordination to the priesthood in 391, he seems to have gone through something of a writer's block, starting but leaving incomplete a treatise on exegetical theory (De doctrina christiana, begun 396 but not completed until 427), another commentary on Genesis (De Genesi ad litteram imperfectus liber, 393-394), and an exposition of Romans (Epistolae ad Romanos inchoata expositio, 394-395). He did manage to finish a verse-by-verse commentary on Galatians, giving the literal sense (Epistolae ad Galatas expositio, 394-395) and a commentary on the Sermon on the Mount (De sermone Domini in monte, 393-396). His Expositio quarundam propositionum ex epistola ad Romanos (394) derives from conversations with the monks at Hippo, who recorded his answers to their questions about Romans; Augustine tells us later that he missed what he eventually came to see as the main point of the epistle.