The final melisma on the word "caput" in the antiphon "Venit ad Petrum" for the ceremony of the washing of the feet on Maundy Thursday in the Sarum rite is the source of the cantus firmus for masses by Dufay, Ockeghem, and Obrecht. Guillaume Dufay's Missa Caput, probably composed between 1440 and 1450, is unified by motto beginnings, a structural similarity between the movements, and cyclic return of the cantus firmus. Johannes Ockeghem's mass, composed between 1460 and 1465, is closely modeled...