Saint Augustine was born Aurelius Augustinus on November 13, 354 CE. He lived his early years in Roman North Africa (now eastern Algeria), where he would have spoken Latin at home and in school. His parents were by no means wealthy, but neither were they destituteAugustine's father Patrick was a small-time landowner (Henry Chadwick writes that, given Ovid's definition of 'pauper' as 'a man who knows how many sheep he has,' "Patrick is likely to have known how many he had"). Augustine's mother, Monica, looms much larger in the Confessions than his father, largely because she was a lifelong Christian who always hoped for Augustine to become a baptized believer. Patrick remained a Pagan until being baptized on his deathbed.
The context of fourth-century Christianity is important to keep in mind throughout much of the Confessions, not only with regard to Augustine's parents but also as a framework for his own lengthy struggle with becoming a Catholic. In the fourth century, Catholicism was one young theological philosophy among many, competing for followers with Christian splinter groups like the Manichees, secular philosophies like Neoplatonism, trendy returns to ancient religions like the cult of Osiris, and the much more traditional propitiation of 'pagan' Greek and Roman deities (this last being the primary religion of the Roman aristocracy which Augustine was trying for a long time to join). Becoming a Catholic or any other kind of orthodox Christian would not have been seen as an entirely normal thing for a person of society to do, and could in fact hinder the kind of successful public career Augustine pursued for much of his young life.
Augustine's teenage years are recounted in the Confessions as being particularly decadent and useless ones. He has almost nothing but regret for his schooling, in which he would have studied literature (mostly in Latin, with some Greek), rhetoric (the art of eloquent speaking, which Augustine would later teach), and dialectic (logical argumentation). Meanwhile, he took a concubine at the age of 17, a decision which went against both Catholic teaching and the societal formula for public success. He would stay with her for some fifteen years, and she bore him a son, Adeodatus.
After his studies at Carthage, where he was an outstanding but quiet student, Augustine returned briefly to Thagaste, setting up a school and a career as a teacher. He left once again for Carthage after the death of a close friend made his hometown unbearable, and continued to teach there. It was at this point that Augustine became a Manichee 'Hearer,' a class of believer less exalted and rigorous than the orthodox Manichee 'Elect.'
Mani, a self-proclaimed prophet of the third century CE, had developed a cosmology designed primarily to deal with the paradox of the presence of evil in a world created by God (who is fundamentally good). Mani claimed that God was not omnipotent, and that He was in fact locked in a constant struggle with an opposite, evil force. This would explain how evil could exist without God willing it. The epitome of this evil nature was held to be matter, encompassing all the sensory pleasures (especially sex). Manichees were therefore purists, following a complex set of dietary and domestic laws (the Elect followed them more strictly than the Hearers, who served them).
Augustine was among a large number of cultivated, well-educated people that joined the Manichees, in part because their texts were written in what Augustine called 'a good Latin' and were presented in handsome volumes. Manicheism was an impressive, colorful faith, depending heavily on its forceful, rhetorically embellished disagreements with Christianity and also on an elaborate cosmology. For ten years, Augustine preferred the well-worded Manichee arguments to the simple parables of the Bible, which he thought crass and uneducated (it didn't help that the Latin Bible was at that time in a particularly poor and unliterary version). Eventually, however, as he moved from Carthage to Rome (to escape rowdy students) and then on to Milan (to escape cheating ones), he became increasingly suspicious of the fantastical cosmology and esoteric laws of the Manichees. Of particular concern were its conflicts with the budding science of astronomy, which was already able to predict things like eclipses. After meeting Faustus, a Manichee wise man, Augustine was ready to explore more truthful, less loquacious forms of belief.
Neoplatonism, which enjoyed a small, erudite following, soon came in to replace Augustine's shaky Manichee beliefs. He was particularly impressed by the Neoplatonic solution to the problem of evil and by its striking philosophical similarity to the Bible. The Bishop at Milan, Ambrose, also had a strong influence on Augustine, teaching him through sermons how to read allegorical depth into the apparently simple parables of the Bible.
With these texts in mind, and after a long process of agonizing decision, Augustine finally committed himself fully to the church after a conversion experience in his garden in Milan in July of 386. He was baptized by Ambrose shortly thereafter, and his mother Monica died shortly after that. The burial of Monica completes the chronological span covered by the autobiographical sections of the Confessions. Augustine would not actually write the Confessions, however, until some thirteen years later, after he had returned once again to Thagaste, this time to start a semi-monastic community.
The immediate reasons for writing his masterpiece seem largely to have to do with his appointment as a bishop at Hippo (also in Northern Africa) in 396. Augustine does not seem to have wanted this postit was more of an offer he couldn't refuse (the forcing of ordination on a person was not uncommon at the time). His critics, however, had even stronger doubts that he was the right man for the job, citing his Manichee past, his cleverness in rhetoric, and his relatively recent conversion. The Confessions were written partly as a response to these critics, openly confessing Augustine's past mistakes, praising God with effusiveness and poetry, and roundly denouncing the Manichees.