The Relative Speed of Tempora in the Period of Dufay

Although in recent years there has been a marked increase in performances and recordings of fifteenth-century music, with a consequent focusing of interest on the performance problems presented by this repertory, a number of fundamental notational ambiguities remain that have received little systematic attention. Among them a particularly pressing problem is that of the relationship between tempus perfectum and tempus imperfectum diminutum in a considerable number of works written between 1440 and 1520.