Listen to Old Christmas Music: II. Peter Warlock: The First Mercy online. Old Christmas Music: II. Peter Warlock: The First Mercy is an English language song and is sung by Royal Ballet Sinfonia. Old Christmas Music: II. Peter Warlock: The First Mercy, from the album Another Night Before Christmas & Scrooge, was released in the year 2011. The duration of the song is 2:37. Download English songs online from JioSaavn.