李惠宗
In October 1224, Lý Huệ Tông ceded the throne to his youngest daughter, the Princess Chiêu Thánh, now the Empress Regnant Lý Chiêu Hoàng. Chiêu Hoàng was only six at that time, and all important decisions in royal court were made by members of the Trần clan. Trần Thủ Độ arranged a marriage between Chiêu Hoàng and Trần Cảnh, the six-year-old son of Trần Thừa. With Trần Cảnh being the Empress Regnant's husband, Trần Thủ Độ was able to overthrow the Lý Dynasty by making Lý Chiêu Hoàng pass the throne to Trần Cảnh, now Trần Thái Tông, in 1225. After the coronation of his son, Trần Thừa acted as Regent of the Emperor, but it was Trần Thủ Độ in the position of Grand Chancellor (Vietnamese: thái sư) who decided both military and civil matters in the royal court; he was respectfully called by Trần Thái Tông and Father of the Nation (Quốc thượng phụ).