Trần Hưng Đạo
The second Mongol invasion of Đại Việt began late in 1284, when the Mongol Yuan forces under the command of Toghan, the prince of Kublai Khan, crossed the border and quickly occupied Thăng Long (now Hanoi) in January 1285, after the victorious battle of Omar in Vạn Kiếp (north east of Hanoi). At the same time Sogetu, second in command of the Yuan army, moved from Champa northward and rapidly marched to Nghe An in the north central region of Vietnam, where the army of the Trần dynasty under general Trần Kien was defeated and surrendered to him. However, the Trần king and the commander-in-chief Trần Hưng Đạo changed their tactics from defence to attack and struck against the Mongols. In April, General Trần Quang Khải defeated Sogetu in Chương Dương and the Trần king won a battle in Tây Kết, where Sogetu died. Soon after, general Trần Nhật Duật also won a battle in Hàm Tử (now Hưng Yên) and Toghan was defeated by General Trần Hưng Đạo. Thus Kublai failed in his first attempt to invade Đại Việt. Toghan hid himself inside a bronze pipe to avoid being killed by the Đại Việt archers; this act brought humiliation upon the Mongol Empire and Toghan himself.