Anglican clergyman and former slave-ship captain who went on to be the author of many hymns, including Amazing Grace.

Amazing Grace

Newton's lyrics have become a favourite for Christians, largely because the hymn vividly and briefly sums up the doctrine of divine grace.
  The song has also become an anthem for supporters of freedom and human rights, both Christian and non-Christian, in part because many assume it to be his testimony about his slave trading past.

Here is one of many versions of the hymn by Judy Collins.