 Therefore, in 1237 Trần Thủ Độ decided to force Trần Liễu to give up his wife Princess Thuận Thiên for the Emperor when she had been already 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.In the fury of losing his pregnant wife, Trần Liễu rose in revolt against the royal family.Emperor Thái Tông felt awkward about the situation and decided to become a monk in Yên Tử Mountain.