The melody of O, come all ye faithful, also known as Adeste Fideles, is most of the time ascribed unto John Francis Wade, a 18th century composer. The truth however is not that clear. Earlier versions of this melody had been around quite some time on the mainland of Europe. The origin of the text however is clear: it's written by Frederick Oakely in 1841. This arrangement is written for SATB + piano/organ.