Saint Augustine, also known as Augustine of Hippo, was a Christian theologian and philosopher born in 354 AD in present-day Algeria. He is best known for his influential works, including Confessions and The City of God, which shaped Western Christianity and philosophy. Augustine's thoughts on sin, grace, and free will have had a lasting impact on Christian doctrine. He became the Bishop of Hippo in 396 AD and played a crucial role in the early Church's development. Augustine's ideas helped to address various theological issues, including the nature of God and the problem of evil, making him one of the most significant figures in Christian history.