The lyrics to the hymn "Amazing Grace" were written by John Newton in 1772, and the traditional tune it is sung to today, "New Britain," was added by William Walker in 1835, after Newton's death. Therefore, there is no single traditional composer, as the lyrics and melody were created separately by different people. 

John Newton (4 August 1725 – 21 December 1807) was an English evangelical Anglican cleric and slavery abolitionist. He had previously been a captain of slave ships and an investor in the slave trade. He served as a sailor in the Royal Navy (after forced recruitment) and was himself enslaved for a time in West Africa. He is noted for being author of the hymns "Amazing Grace" and "Glorious Things of Thee Are Spoken".

William Walker (May 6, 1809 – September 24, 1875) was an American Baptist song leader, shape note "singing master", and compiler of four shape note tunebooks, most notable of which are the influential The Southern Harmony and The Christian Harmony, which has been in continuous use (republished 2010).