The earliest form is known as Hinayana or Theravada. Its monks read texts in Pali, an ancient Indo-European language which, like Sanskrit, is no longer generally spoken. This school was more a philosophy than a religion, stressing the striving for personal nirvana. In the first century C.E. Mahayana (Great Vehicle) Buddhism emerged in Asia. The Buddha became a de facto deity and past and future buddhas became a kind of pantheon. The idea of bodhisattvas, enlightened ones who postponed personal nirvana to help others and to better the conditions of humanity, developed in Mahayana. This is the most widely practiced form of Buddhism in China and elsewhere in Asia. A third form of Buddhism, called Tantrism or Vajrayana or Tibetan Buddhism, developed in the seventh century C.E. and is most popular in the Himalayan region (Tibet, Nepal). Tibetan Buddhism is an aspect of Mahayana in that it stresses bodhisattvas, but it has a much more complex mythological system, based on bodhisattvas who are clearly seen with their female counterparts as deities.