Malyn Newitt examines how the ideas and institutions of a late medieval society were deployed to aid expansion into Africa and the Atlantic islands, as well as how, through rivalry with Castile, this grew into a worldwide commercial enterprise. Finally, he considers how resilient the Portuguese overseas communities were, surviving wars and natural disasters, and fending off attacks by the more heavily armed English and Dutch invaders until well into the 1600s. Including a detailed bibliography and glossary, is an invaluable textbook for all those studying this fascinating period of European expansion