Even though it was a time of great military strength for the Northern Wei, because of Rouran harassment in the north, they could not fully focus on their southern expeditions. After uniting the north, Emperor Taiwu also conquered the strong Shanshan kingdom and subjugated the other kingdoms of Xiyu, or the Western Regions. In 450, Emperor Taiwu once again attacked the Liu Song and reached Guabu (瓜步, in modern Nanjing, Jiangsu), threatening to cross the river to attack Jiankang, the Liu Song capital. Though up to this point, the Northern Wei military forces dominated the Liu Song forces, they took heavy casualties. The Northern Wei forces plundered numerous households before returning north.