In order to counter the Xiongnu attacks, Emperor Kao-tsu took some precautionary measures. In 201 BC, he sent Hsin, the king (prince/ruler) of the Han region, to the Ma-i region to defend its borders against the Xiongnus.In the fall of the same year, Hsin, who had been besieged by Mo-tu's forces for a long time, sent envoys to the Xiongnus several times to seek peace. His frequent contacts with the Xiongnus led to his being denounced as a traitor by the Han emperor. Realizing the situation, Hsin surrendered the city of Ma-i to the Xiongnu, fearing he would be killed.[1][2][3]