Augustine probably began work on the Confessions around the year 397, when he was 43 years old. Augustine's precise motivation for writing his life story at that point is not clear, but there are at least two possible causes.
First, his contemporaries were suspicious of him because of his Classical, pagan-influenced education; his brilliant public career as a rhetor; and his status as an ex-Manichee. In the midst of Augustine's prominent role in the Donatist controversies, he was suspected both by his Donatist enemies and by wary Catholic allies. One purpose of the Confessions, then, was to defend himself against this kind of criticism, by explaining how he had arrived at his Christian faith and demonstrating that his beliefs were truly Christian.
Another motivation may have been a bit of correspondence between Augustine's close friend Alypius and a notable Christian convert, Paulinus of Nola, a Roman aristocrat who had renounced the world and his immense family fortune upon converting to Christianity. Alypius wrote to Paulinus and sent him some of Augustine's works. Paulinus wrote back to ask Alypius for an account of Alypius' life and conversion. Alypius apparently conveyed the request to Augustine, which may account for the space devoted to Alypius' life story in Book 6.
The word "confession" has several senses, all of which operate throughout the work. Confession can mean admitting one's sins, which Augustine does with gusto, confessing not only his ambition and his lust but also his intellectual pride, his misplaced faith in Manichaeism, and his misunderstanding of Christianity. Confession also means a statement of belief, and this aspect is reflected in Augustine's detailed account of how he arrived at his Christian beliefs and his knowledge of God. Finally, confession means a statement of praise, and in the Confessions, Augustine constantly gives praise to the God who mercifully directed his path and brought him out of misery and error. In essence, the Confessions is one long prayer.
