Biography of Liu Yu Part 2(21)

By the early period of Liu and Song Dynasties, the territory of the Southern Dynasty from Tongguan east to the south of the Yellow River to Qingzhou had become the largest dynasty in the Eastern Jin and Southern Dynasties.
Liu Yu made indelible achievements in his northern expeditions. Although Guanzhong was later lost, Henan, Shandong and Huaibei were included in the territory of the Southern Dynasty. He pushed the defensive line of the southern dynasty to the line of Tongguan and the Yellow River, and protected the Jianghuai river basin. Later, the wars between the Song and Wei Dynasties were mostly carried out in these lands, which made the Yangtze River valley quiet for a long time, and provided the northern boundary barrier for the emergence of the "rule of Yuan Jia".