Buddhism was introduced into Sri Lanka in the 3rd century BCE by Mahinda, the son of King Ashoka, and has prevailed there ever since. This means that Sri Lanka has been Buddhist longer than any other country. Mahayana and Vajrayana were popular at various times but Theravada always predominated and since the 12th century has been the only form of Buddhism there. During the colonial period (16th century to 1947), Buddhists and Buddhism were often persecuted and always disadvantaged. In 1956 Buddhism became in effect the state religion. Sri Lankan monks have a long tradition of travelling widely and spreading Buddhism as they do so. The first Buddhist monks ever to go to Europe were two Sri Lankans who arrived in England in 1819.