In the century after 1560, Europeans fought religious wars that pitted Catholics against Protestants. These conflicts also had political, constitutional, economic, and social implications. At the same time, Europe was transformed by its contacts with Africa, Asia, and the New World, and by the birth of capitalism. Trade expanded, new social classes emerged, and Europeans speculated about the diversity of human cultures and races. The Portuguese were the first to establish a great trading empire along the coast of Africa. Columbus paved the way for a Spanish empire with the discovery of the New World. A commercial revolution took place within Europe, against the backdrop of an expanding population and a commercial revolution. The landed aristocracy, the peasantry, the middle classes, and the working poor became the predominant classes of European society under the new economic system. Meanwhile, Philip II of Spain attempted to enforce Catholicism within his vast empire. France witnessed a feudal rebellion against the monarchy, as well as religious war, in the conflicts between Huguenots and Catholics. In Germany, the Thirty Years' War pitted member states against the emperor, and turned into an international conflict involving most of Europe. With the resolution of the Thirty Years' War, religion would no longer be a primary cause for political conflict between European sovereign powers.