This dissertation will examine the patronage of three members of the Altieri family, Gaspare, Angelo and Cardinal Paluzzo, between 1670 and 1705. My study of Altieri patronage will address an aspect of early modem Italian society that has yet to be explored, namely adoption. When aristocratic families faced extinction due to the lack of a male heir, they often adopted another individual of a similar rank to carry on the family name. Although common in the seventeenth century, the practice has not been studied in modem scholarship on the period. The adopted members of the Altieri family were prolific patrons and their commissions represent some of the most important works in Rome at the time. I will study key Altieri monuments, including the Palazzo Altieri, the Altieri chapel in the church of San Francesco a Ripa (renovated by Bernini c. 1674), the Altieri chapel in Santa Maria in Campitelli (Sebastiano Cipriani, 1705), the Villa Altieri and the ducal complex of a palace and church in Monterano. As they were adopted by Pope Clement X Altieri (1670-76), the patronage of these three noblemen has been perceived as a monolithic expression of Altieri family identity and socio-political ambition. However, these commissions often honour the adoptees' biological family, the Albertoni. My dissertation will explore the relationship between the adoptees' complex familial ties and their patronage. As the ideas of art and adoption have never been investigated in seventeenth-century patronage studies, there is a unique opportunity in this topic to reassess one of the fundamental forces in seventeenth-century patronage, namely the shape of the family. Through the visual arts, this dissertation will examine the process of constructing kinship, and present an interpretation of the family in the seventeenth century as an entity far more fluid than has hitherto been supposed.