Augustine later told it, his conversion was prompted by hearing a child's voice say "take up and read" (). Resorting to the sortes biblicae, he opened a book of St. Paul's writings (codex apostoli, 8.12.29) at random and read Romans 13: 13–14: Not in rioting and drunkenness, not in chambering and wantonness, not in strife and envying, but put on the Lord Jesus Christ, and make no provision for the flesh to fulfill the lusts thereof. He later wrote an account of his conversion in his Confessions (), which has since become a classic of Christian theology and a key text in the history of autobiography. This work is an outpouring of thanksgiving and penitence. Although it is written as an account of his life, the Confessions also talks about the nature of time, causality, free will, and other important philosophical topics. The following is taken from that work: Ambrose baptized Augustine and his son Adeodatus, in Milan on Easter Vigil, 24–25 April 387. A year later, in 388, Augustine completed his apology On the Holiness of the Catholic Church. That year, also, Adeodatus and Augustine returned home to Africa. Augustine's mother Monica died at Ostia, Italy, as they prepared to embark for Africa. Upon their arrival, they began a life of aristocratic leisure at Augustine's family's property. Soon after, Adeodatus, too, died. Augustine then sold his patrimony and gave the money to the poor. He only kept the family house, which he converted into a monastic foundation for himself and a group of friends. Furthermore, while he was known for his major contributions regarding Christian rhetoric, another major contribution was his preaching style. After converting to Christianity, Augustine turned against his profession as a rhetoric professor in order to devote more time to preaching. In 391 Augustine was ordained a priest in Hippo Regius (now Annaba), in Algeria. He was especially interested in discovering how his previous rhetorical training in Italian schools would help the Christian Church achieve its objective of discovering and teaching the different scriptures in the Bible. He became a famous preacher (more than 350 preserved sermons are believed to be authentic), and was noted for combating the Manichaean religion, to which he had formerly adhered. He preached around 6,000 to 10,000 sermons when he was alive; however, there are only around 500 sermons that are accessible today. When Augustine preached his sermons, they were recorded