The "Salve Regina" is unique among English music of the period in that its cantus firmus, drawn from the melisma on the word "caput" in the Sarum antiphon "Venit ad Petrum", is the same as that from three earlier "Caput" masses by composers from elsewhere: Jacob Obrecht, Johannes Ockeghem, and an anonymous composer once thought to be Guillaume Dufay. Recent research has suggested that this third mass was actually by an unknown Englishman working in the early 15th century, and is the original for the later three works. The "Salve Regina", being based on a votive antiphon for Maundy Thursday, was probably intended for use on that day.