In military history, it is common to find people aligning themselves and forming alliances in accordance with their common objectives, and it is striking how a shared enemy can unite even the unlikeliest of allies, as mentioned last time. This phenomenon is particularly common in Chinese dynasty history where the historical conflicts between various ethnic groups can be analysed in terms of shifting allegiances. In the Song (宋) Dynasty (10th-13th century AD), the sovereign Han (漢) group was harassed by numerous ethic groups on their northern border (remnants from previous dynasties (南北朝, 五胡十六國)), namely Qidan (契丹), Jin (金) and the Mongols (蒙古). They clashed with the Qidan first (11th century AD), and in order to defeat them, they allied with the Jin, who had geographical advantage over the Qidan, and helped develop and strengthen the Jin army, who became quite formidable. The Jin then became the Hans’ greatest enemy up north and directly threatened the Song Dynasty by capturing their emperor and forced them to emigrate southwards (靖康之恥). When the Mongols rose in prominence due to the rise of the greatest warrior in history (Genghis Khan), the Hans made alliances with the Mongols and defeated the Jin (the survivors of Jin became the ancestors of the Manchurians who later ruled China from the 17th century onwards and formed the last dynasty (清 Qing) in China’s history). Then followed the greatest military conflict in the Song Dynasty, namely the Mongolian invasions which not only swept across Eurasia to Europe but also conquered the Hans in the south and crushed the Song Dynasty once and for all. The Yuan (元) dynasty was hence established which lasted around one hundred years before the Mongolians were banished by the Hans back to the north of China which led to another Han-led dynasty, Ming (明).
By recognizing the various allegiances and alliances in the Song Dynasty, there seem to be clear cycles in the historical evolution of the various ethnic groups in historical China, which seems to be a characteristic of Chinese dynastic history. More on this to follow.