During the sixteenth, seventeenth, and eighteenth centuries, the three Portuguese military orders of Christ, Santiago and Avis became that kingdom's most important institutions for rewarding services to the Crown. Membership in these military orders was highly prized as status symbols and because of the orders' "purity of blood" statutes, these knighthoods were more highly esteemed than mere patents of nobility, especially since such knighthoods automatically ennobled. Francis A. Dutra has written widely on the Portuguese military orders of Christ, Santiago and Avis - a topic generally neglected by students of early modern Portugal. This volume brings together a selection of his pioneering essays. Based extensively on archival research, they reflect his special interest in social mobility and use of the knighthoods for patronage, while particular sections focus on the role of the orders in the Portuguese maritime expansion and in India and Brazil, and on the medical profession. The collection includes English translations of four studies that originally appeared in Portuguese, as well as a detailed index, in itself a useful research tool.