This project proposes an intensive study of the music of Jacobus Clemens non Papa, one of the greatest composers of the mid sixteenth century, yet one that is still very insufficiently understood. The project proposes a historical, analytic, and practical engagement with Clemens' music through: (i) repertorial and analytical study through performance, including addressing the issues posed by performing from original sources; (ii) study of how Clemens' music relates to that of his contemporaries, predecessors, and successors; and (iii) a re-examination of three important primary sources in palaeographical and codicological terms. The focus on this composer forms part of a reconsideration of his life and work around the 500th anniversary of his birth.