When did buudhism the official religion of Tibet start?

Buddhism became the official religion of Tibet in the 7th century during the reign of King Songtsen Gampo, who is credited with establishing the first Tibetan state and promoting the religion. He married a Chinese princess, Wencheng, who played a significant role in introducing Buddhist teachings and practices to Tibet. This period marked the beginning of the integration of Buddhism into Tibetan culture and society, leading to its prominence in the region.