Nam quoc son ha is one of the most famous poems in the national literature. Due to the error of historian Tran Trong Kim in the beginning of the 20th century, many Vietnamese scholars have automatically recognised that the poem was written by General Ly Thuong Kiet. As a result of scientific research conducted in many years, Professors Ha Van Tan and Bui Duy Tan have a firm basis to confirm that the author of Nam quoc son ha is not Ly Thuong Kiet. Recently, Prof. Le Manh That tended to attach the "authorship" of this work to Buddhist Zen Master Phap Thuan (915-990) who lived during the resistance war against Chinese Song Dynasty during the reign of King Le Dai Hanh (according to Vietnamese Buddhist History, Volume 2, Ho Chi Minh city Publishing House, 2001). As presented in the article, we do not have sympathy for Professor Le Manh That's views due to his impulsive and subjective explanations
moreover, no historical documents existing after more than a thousand years could prove Phap Thuan's authorship over the poem Nam quoc son ha
meanwhile, the poem may be composed before the times of Phap Thuan.