Masculinity was an important concept in early modern Spanish social and cultural life. In the fifteenth and sixteenth centuries, Spanish noblemen were expected to perform masculine roles that enhanced their power, wealth, and status, thus benefiting their families. Recent scholarship on early modern Spanish masculinity has emphasized both its flexible and changing nature and the importance of sexuality in understanding how it functioned. Masculinity was an ambiguous and dangerous performance in the fifteenth and sixteenth centuries. The policy of a flexible patriarchy that depended heavily on the abilities and activities of women is one that characterizes the nobility across early modern Europe. The mistresses of Spanish noblemen are a more ambiguous group. They did not automatically have the same rank and status as noble wives, and their rights and powers varied accordingly. Mistresses could make the noble family a contested space if they claimed legitimacy or formal inheritance rights.