Schöffer's Cantiones tell a fascinating story of South-North, Catholic-Protestant co-operation. The Cantiones quinque vocum selectissimæ (Strasbourg: Peter Schöffer the Younger, 1539) are a collection of 28 Latin five-voice motets by composers including Gombert, Willaert, and Jacquet of Mantua. This was Schöffer's first book of Latin motets as well as his last ever musical publication; he was granted an imperial privilege to print it by King Ferdinand I. The pieces had been sent to Schöffer by Hermann Matthias Werrecore, the choirmaster of the Duomo of Milan. However, this was at a time when no liturgical Latin choral singing took place in Strasbourg, following one of the harshest reformations - musically-speaking - across Europe. This book comprises a critical study of the anthology in terms of the circumstances of its assemblage and printing, its confessional significance, and the music itself. It considers the nature of the connection between Schöffer and Werrecore, and why a Protestant publisher based in Protestant Germany would try to sell Latin music that was endorsed by a Catholic monarch and emphatically had no chance of being performed in church in its place of publication. In addition, the monograph includes considerations of the motets themselves, brief biographical details of the composers - including the lesser-known ones (e.g. Ferrariensis, Sarton, Billon) - and a full list of all concordant sources. It will be of interest to performers and scholars alike, combining elements of historical research, musical criticism and - via the transcriptions hosted online - performance.