 632-646), said to be a student of the Chinese master Daoxin (道信; 580-651).Seon was later popularized especially by Sinhaeng (神行; 704-779) in the latter part of the eighth century and by Doui (道義; d. 825) at the beginning of the ninth century.From then on, many Koreans studied Chan in China and, upon their return, established their own schools at various mountain monasteries with their leading disciples.