Trần Thủ Độ
According to "Đại Việt sử ký toàn thư", Thái Tông and his wife, the Empress Chiêu Thánh, did not have their first son for some time. This situation worried the grand chancellor Trần Thủ Độ because he had profited from similar circumstances with the Emperor Lý Huệ Tông in overthrowing the Lý dynasty. Therefore, in 1237 Trần Thủ Độ decided to force Prince Hoài Trần Liễu, Thái Tông's elder brother, to give up his wife, Princess Thuận Thiên, for the Emperor when she had been pregnant with Trần Quốc Khang for three months. After the royal marriage, Thuận Thiên was entitled the new empress of the Trần dynasty, while Chiêu Thánh was downgraded to princess. Furious at losing his pregnant wife, Trần Liễu rose in revolt against the royal family. Meanwhile, Thái Tông felt awkward about the situation and decided to become a monk at Yên Tử Mountain in Quảng Ninh. Finally Trần Thủ Độ successfully persuaded Thái Tông to return to the throne, and Trần Liễu had to surrender after judging that he could not stand with his fragile force. All soldiers who participated in this revolt were killed; Trần Thủ Độ even wanted to behead Trần Liễu but was stopped by Thái Tông.