This study investigates an almost unknown musical culture: that of the cloistered nuns in one of the major cities of early modern Europe. These women were the most famous musicians of Milan, and the music composed for them opens up a hitherto unstudied musical repertory, which allows insight into the symbolic world of the city.

Even more importantly, the music actually composed by four such nuns - Claudia Sessa, Claudia Rusca, Chiara Margarita Cozzolani, and Rosa Giacinta Badella - reveals the musical expression of women's own devotional life.

The two centuries of battles over nuns' singing of polyphony, studied here for the first time on the basis of archival documentation, also suggest that the implementation of reform in the major centre of post-Tridentine Catholic renewal was far more varied, incomplete, subject to local political pressure and individual interpretation, and short-lived than has commonly been assumed.

Other factors that marked these women's musical lives and creative output - liturgical traditions of the religious orders, the problems of performance practice attendant upon all-female singing ensembles - are here addressed for the first time in the musicological literature.