Musicologists are increasingly focusing upon less formal private "institutions" and traditions of patronage: informal acad. and soc, the activities of individuals, and convivial aristocratic co. Early 16th-cent. Florence was characterized by the practices of a series of these vital institutions. Such informal institutions had considerable virtues as agents of patronage; their less routinized practices freed them to engage in experimentation that the more formal institutions would not support. This study reconstructs the memberships, cultural activities, and musical exper. of these informal Florentine institutions and relates them to the emergence of the madrigal, the foremost musical genre of early-modern Europe. Richly illus. with visual materials and musical examples.