The received view of the Tudor composer Thomas Caustun is of a minor and relatively uninteresting figure. That view is adjusted, however, by the discovery among his works of contrafacta of music by Nicolas Gombert, Philippe van Wilder, Rogier Pathie and Sebastiano Festa. This article considers the reasons why Caustun made these adaptations, and why they they were published under his name, rather than those of their true composers, in John Day's anthology of Protestant church music, Mornyng and Evenyng Prayer and Communion (London, 1565).