Dharmakirti (7th centrury) is one of the most important Buddhist philosophers. Born as a South Indian Brahmin, he studied with Dharmapala at Nalanda University where he became a teacher and was one of the Buddhist founders of Indian philosophicallogic. His writings treat basic questions concerning the nature of knowledge, its forms, and its relation to the external world. He profoundly influenced Mahayana Buddhism and South Asian philosophy as a whole. Dharmakirti was one of the principle spokesmen of the Yogachara (Skt.), Chittamatra (Tib.) or Mind Only school of Indian Buddhist philosophy, which greatly influenced Tibetan Buddhism, especially the Nyingma school and the highest teachings in Tibetan Buddhism Dzogchen.