During the Trần Dynasty, the armies of the Mongol Empire under Mongke Khan and Kublai Khan, the founder of the Yuan dynasty invaded Vietnam in 1257 AD, 1284 AD, and 1288 AD. Đại Việt repelled all attacks of the Yuan during the reign of Kublai Khan. The key to Đại Việt's successes was to avoid the Mongols' strength in open field battles and city sieges - the Trần court abandoned the capital and the cities. The Mongols were then countered decisively at their weak points, which were battles in swampy areas such as Chương Dương, Hàm Tử, Vạn Kiếp and on rivers such as Vân Đồn and Bạch Đằng. The Mongols also suffered from tropical diseases and loss of supplies to Trần army's raids. The Yuan-Trần war reached its climax when the retreating Yuan fleet was decimated at the Battle of Bach Dang (1288). The military architect behind Dai Viet's victories was Commander Trần Quốc Tuấn, more popularly known as Trần Hưng Đạo. In order to avoid disastrous campaigns, the Tran and Champa acknowledged Mongol supremacy.