Treaty of Saigon
He was the best known opponent of collaboration in the south of Vietnam and was regarded as the poet laureate of the southerners who continued to defy the Treaty of Saigon which ceded southern Vietnam to France, disobeying the royal orders of Emperor Tự Đức to continue harassing the French forces. His epic poem, "Lục Vân Tiên", remains one of the most celebrated works in Vietnamese literature.