More than thirty years ago, Jacques Handschin drew general attention to certain striking melismas in Ambrosian chant. He identified these as tropes – referring to them as ‘prototypes’ – and he noted the importance in their construction of repetitions, both exact and approximate, repetitions that involved both brief motives and lengthy passages.

One theory of the origin, development and structure of the chant repertoire is that the thousands of individual pieces in it arose from the adaptation of new texts to a small number of melodies, or melodic ‘themes’. First put forward by Gevaert, this theory, which will be referred to here as the thematic theory, has, in different forms, been the basis of studies of the transmission of antiphons, and is now being applied to the repertories of Old-Roman and Ambrosian chant. The main demonstration of the validity of the theory must take place, of course, in studies of the repertoire itself; we shall be convinced if musical and liturgical evidence supports the idea of adaptation and suggests a chronological development. It is nevertheless important to examine music-historical witnesses ancillary to the chant repertoire, for it is often the case that related documents reveal something unexpected about the main repertoire, or serve as a means of confirming points for which evidence is lacking.

The manuscript Vatican City, Vatican Library, Vaticanus Latinus 10781 is a 15th-century antiphonal from Veroli, an Italian town located south of Rome and north of Cassino. It is particularly interesting for the study of late medieval chant, since it contains a virtually complete setting of the office of Mary, mother of the apostles John and James; a closer examination of the chant texts identifies the saint as Mary of Salome. Mary of Salome is also known as one of the Three Marys, the other two being Mary of Cleophas and Mary the mother of the Lord. Although two exemplars of an office of the Three Marys are preserved in Carmelite manuscripts, the office presented in our codex remains distinct from the office of the Three Marys.