The Age of Enlightenment is also called the Age of Reason because it marked a change from the medieval tradition of scholasticism based on Christian dogma and the often occultist approach of Renaissance philosophy. Instead, reason became the central source of knowledge, beginning the era of modern philosophy, especially in Western philosophy. The period was typified in Europe by the great system-builders, philosophers who presented unified systems of epistemology, metaphysics, logic, and ethics and often politics and the physical sciences as well.