 After the coronation of Trần Cảnh, now Trần Thái Tông, Trần Thủ Độ was appointed grand chancellor and regent of the Emperor.As the most powerful figure of the royal court and the Trần royal family, Trần Thủ Độ was responsible for both civil and military matters in Đại Việt; his successful governing was considered by historical books as the crucial factor that not only led to the stability of the early Trần dynastic period but also contributed to the victory of Đại Việt over the first Mongol invasion.Although a skilled and devoted official of the Trần Dynasty, Trần Thủ Độ still remains a controversial figure in the history of Vietnam for several ruthless decisions to dispose of members of the Lý royal family, and for his responsibility in the forced marriage between Trần Thái Tông and his brother Trần Liễu's wife, Princess Thuận Thiên, which was highly criticized by feudal historians.