The story of the hymn "Amazing Grace" is familiar to many. Apparently the author, John Newton, a slave trafficker was caught in a wild storm on one of his slave ships. Begging God to save him, the ship miraculously did not sink and thereafter, Newton quit the slave trade and became a Christian.
However, as Newton admits, the story was a bit more complicated than that. His father was a shipmaster, and Newton gained nautical skills by going on trips with him. He was pressganged (basically kidnapped) at the age of 18 into naval service where he was flogged brutally in front of his comrades after trying to desert. Embittered by this experience, he joined a slave ship. However, he did not get on with the crew, who dropped him in West Africa where he consorted with slave traders and himself became a slave for a bit.
Returning to England in 1748, his ship was caught in a severe storm and seemed about to sink. This is when Newton began his conversion to the faith, falling to his knees and begging God to save his life. The storm died down after his prayers.
After this experience, Newton began to read the Bible, but still continued in the slave trade for several more years. After suffering a stroke in 1754 he gave up seafaring and the slave trade. He himself admitted that it took him a while to become a true Christian.
In 1764, Newton became an Anglican priest. His song "Amazing Grace" was referenced in Harriet Beecher Stowe's "Uncle Tom's Cabin" and was recorded by Aretha Franklin, Johnny Cash and Elvis. Recently, President Obama burst into the familiar tune during a memorial service at the church shooting in Charleston, S.C.