Tibetan Buddhism is a Mahayana form of Buddhism having as its spiritual head, the Dalai Lama. It was born out of the fusion of Vajrayana Buddhism and the indigenous Bon tradition.
It is broadly divided into four main sects: (1)Nyingmapa ("The Ancient Ones") (2)Kagyupa ("Oral Lineage") (3)Sakyapa ("Grey Earth") (4)Gelugpa ("Way of Virtue")
Before Buddhism, the dominant religion of Tibet was the indigenous 'Bon' faith. Buddhism is said to have spread to Tibet in the 7th century during the reign of King Songtsen Gampo, though there is no definite proof of its presence before the next century. He was married to a Nepalese princess as well as a Chinese Princess. It is believed that the Nepalese princess carried the teachings of the Buddha with her to Tibet. And As parts of their dowry (gifts for the bride), they brought many Buddhist scriptures and statues to the court. As the years passed a number of different sects evolved; and it has even integrated to politics of the region and spread to regions around Tibet.