The appearance of the solo voice in church music in 1602, in Lodovico da Viadana's Cento concerti ecclesiastici, initiated a development that would soon parallel secular solo song. This series of Italian solo motets makes available for the first time many of these rich sources of seventeenth-century sacred music. The series spans the major part of the seventeenth century, from 1621 to 1695. It includes works by composers from major cities and provincial towns. Three composers are represented by multiple collections: Maurizio Cazzati (6); Bonifazio Graziani (6); and Isabella Leonarda (5). In each case, the solo motet forms a major component in that composer's oeuvre; their collections provide comprehensive "textbooks" for the study of the genre.