St. Augustine, Bishop of Hippo and Doctor of the Church, was the son of Saint Monica. He was raised a Christian, but lost his faith in youth and led a wild life. He lived with a woman from the age of 15 through 30 and fathered a son. After investigating and experimenting with several philosophies, he became a Manichaean but was converted by the prayers of his mother and the help of Saint Ambrose of Milan, who baptized him. He then spent the remainder of his life doing great things. His later thinking can be summed up in a line from his writings: "Our hearts were made for You, O Lord, and they are restless until they rest in You."