 As a result, Kublai Khan began to expose his attempt to take over the southern countries like Đại Việt or Champa.Aware of the situation, Thánh Tông and Nhân Tông began to prepare the Trần dynasty for the obvious and inevitable war while tried to keep a flexible policy with the Yuan dynasty.First, Prince Chiêu Văn Trần Nhật Duật was appointed for the mission of pacifying the revolt led by Trịnh Giác Mật in Đà Giang by diplomatic means in order to keep the country in stability before the war.