The History of Buddhism spans from the 6th century BCE to the present, starting with the birth of the Buddha Siddhartha Gautama. This makes it one of the oldest religions practiced today. Throughout this period, the religion evolved as it encountered various countries and cultures, adding to its original Indian foundation Hellenistic as well as Central Asian, East Asian, and Southeast Asian cultural elements. In the process, its geographical extent became considerable so as to affect at one time or another most of the Asian continent. The history of Buddhism is also characterized by the development of numerous movements and schisms, foremost among them the Theravada, Mahāyāna and Vajrayana traditions, punctuated by contrasting periods of expansion and retreat.