The archconfraternity of SS. TrinitÃ was one of the less well-known institutions for musical patronage in sixteenth-century Rome. Yet in focusing on its activities in the period 1550-1650, this book sheds light on networks of urban patronage that were equally important in commissioning the sacred music of the period as the Cappella Pontificia and the Cappella Giulia at St Peter's. Not only did SS. TrinitÃ provide Palestrina with his only known major involvement in sacred music outside the Cappella Giulia after 1571 it also employed at some time or another every major composer active in the city. Noel O'Regan discusses the importance of SS. TrinitÃ in the sphere of Roman sacred music during this period and the ways in which this music was affected by social and religious factors in the play for power and prestige in post-tridentine Rome.