Theravada Buddhism is believed to have first reached Laos during the 7th – 8th centuries CE, via the kingdom of Dvaravati. During the 7th Century, tantric Buddhism was also introduced to Laos from the kingdom of Nan-chao, an ethnically Tai kingdom centered in modern-day Yunnan, China. The Nan-chao kingdom also likely introduced the political ideology of the king as defender and protector of Buddhism, an important ideological tie between the monarchy and the "sangha" in much of Southeast Asia. We also know very little about the transfer of Buddhism to the region which today is called Laos, but the current state of research suggests that Buddhism did not come in a single movement. According to Michel Lorrillard "the conditions surrounding this penetration remain very imprecise, due to the long duration of this process". From a general perspective, research on the early history of Lao Buddhism had advanced slowly, but recent studies are also signalling progress.