Nyingma, also referred to as Ngagyur, is the oldest of the four major schools of Tibetan Buddhism. The Nyingma school was founded by Padmasambhava as the first translations of Buddhist scriptures from Pali and Sanskrit into Tibetan occurred in the eighth century. The establishment of Tibetan Buddhism and the Nyingma tradition is collectively ascribed to Khenpo Shantarakshita, Guru Padmasambhava, and King Trisong Detsen, known as Khen Lop Chos Sum.