The late Renaissance sculptor Leone Leoni (1509-1590) came from modest beginnings, but died as a nobleman and knight with a house and art collection envied by the nobility. Leoni's success as an artist and his social and intellectual achievements outdid those of any of his predecessors. Through extensive archival research, Kelley Helmstutler Di Dio sheds new light on Leoni's background and character, as well as on unknown aspects of his career, his social position in Milan, and the contents of his impressive art collection. Di Dio has collected and analyzed a sizeable body of unpublished material that, along with contemporary accounts, fleshes out Leoni's multiple roles as imperial sculptor, aristocrat, scholar, and criminal. She further examines the visual manifestations of these roles in his house, collection, and tomb, as well as Leoni's influence on artists in Italy, Spain and the Netherlands. This study provides a specific case study of an artist's struggle and triumph over existing social structures that marginalized the Renaissance artist and it describes the model for later artists in other European countries who strove for the same high status. It situates Leoni and his work within the complex political, social and economic contexts of northern Italy and the Spanish court of the sixteenth century.