Confessions is an autobiographical work by Saint Augustine of Hippo, consisting of 13 books written in Latin between AD 397 and 400. The work outlines Saint Augustine's sinful youth and his conversion to Christianity. The work provides an unbroken record of Saint Augustine's development of thought and is the most complete record of any single person from the 4th and 5th centuries. It is a significant theological work, featuring spiritual meditations and insights. In the work, Augustine writes about how he regrets having led a sinful and immoral life. He discusses his regrets for following the Manichaean religion and believing in astrology. He writes about his friend Nebridius's role in helping to persuade him that astrology was not only incorrect but evil, and Saint Ambrose's role in his conversion to Christianity. The first nine books are autobiographical and the last four are commentary and significantly more philosophical. He shows intense sorrow for his sexual sins and writes on the importance of sexual morality. The books were written as prayers to God, thus the title, based on the Psalms of David. The work is thought to be divisible into books which symbolize various aspects of the Trinity and trinitarian belief. Confessions is generally considered one of Augustine's most important texts. It is widely seen as the first Western Christian autobiography ever written, and was an influential model for Christian writers throughout the Middle Ages.