In the early 17th century, when Spanish interests often competed with those of the House of Austria, three women in the court of Philip III of Spain - Empress Maria, Philip's grandmother; Margaret of Austria, Philip's wife; and Margaret of the Cross, Philip's aunt - worked behind the scenes to win favour for the causes of the Austrian Habsburgs. In this book, historian Magdalena Sanchez offers an examination of the political power wielded by these three women. Sanchez examines the ways that women used religious piety, childbearing, illnesses such as melancholy, and marriage arrangements to sway political decisions. They employed distinct strategies and languages at informal occasions such as meals, masquerade celebrations and religious ceremonies to influence the political scene. By incorporating women into informal political networks, this work aims to break new ground in the study of early modern European politics.