Over the eleventh and twelfth centuries, a rise in agricultural production led to an increase in Western Europe’s wealth and population. The chaos of the tenth and eleventh centuries had brought about the origin of a feudal system dominated by knights. Feudal Europe was thus able to respond to the Byzantine Empire’s requests for help when its field army was annihilated by Saljuq Turks, resulting in the First Crusade and establishment of a set of Crusader States in the Eastern Mediterranean, but these Crusader states were gradually conquered by Muslim powers over the next two centuries. An army of Crusaders would eventually defeat and break up the Byzantine Empire, and although that empire would be re-established, it was never strong enough to resist the pressure of the Ottoman Turks, who finally conquered it in 1453.
As Western Europe grew in population and urbanized, the urban cathedral schools became the center of an increase in intellectual activity over the twelfth century known as the Twelfth-Century Renaissance. Thinkers of the Twelfth-Century Renaissance used the philosophy of the Ancient Greeks and Arabs to understand the world, and in the thirteenth century the intellectual movement known as scholasticism would seek to reconcile Christianity with Arabic and Ancient Greek Philosophy. By the end of the Middle Ages, Europe’s intellectuals would seek to study the writings of the Ancient Greeks and Romans, and not the commentators of the previous thousand years. This movement was known as Renaissance humanism.
Europe’s states—with the notable exception of the Holy Roman Empire—gradually consolidated, but the fourteenth and fifteenth centuries saw increasing interstate warfare. The states that emerged out of this endemic war, however, were more militarily powerful and more centralized. At the same time, sailors in the service of Spain and Portugal were exploring the Atlantic and West Africa until the close of the fifteenth century, when Western Europeans discovered the existence of the continents of the Western Hemisphere.