fit to be a premier of a state". In 636 BC, after the death of Duke Hui, Duke Mu of Qin escorted Chong'er back to Jin with an army, and Chong'er was installed as the Duke of Jin. Duke of Jin Duke Wen undertook several major reforms of the state's military and civil institutions, partly in order to fill the gaps that had been caused by the slaughter of the ducal house previously. These included the formation of a three-army system, with an upper, middle and lower army each commanded by a General and a Lieutenant-General. The state was further invigorated by the many capable leaders Duke Wen had gathered from his wanderings, who were given senior military and governmental posts. With this army, as well as his considerable prestige, Duke Wen was able to absorb many of the states around Jin, greatly increasing its extent, while also subjecting others as vassals; its vassal states included Cao, which he attacked in reprisal for the rude treatment afforded him during his exile. At the same time, he took the political stance of supporting the Eastern Zhou court and King Xiang of Zhou. When in 635 BC King Xiang was deposed and driven out by his brother, Duke Wen led a coalition of states which re-installed him as King. At the same time, the northward expansion of the State of Chu was also resisted by Duke Wen; the two states' conflict was mostly played out among the smaller states which lay between their territories and formed alliances with one state or another. In 633 BC, Chu invaded the State of Song, which was an ally of Jin; Duke Wen led his coalition, including troops from Qin, Qi and Song, and won a decisive victory over Chu forces at the Battle of Chengpu in 632 BC. This battle checked Chu's northern expansion for decades, while cementing Duke Wen's position; the next year, he convened a large coalition of rulers at Jiantu, and was confirmed as hegemon over the other states, becoming one of the Five Hegemons. Duke Jin died in 628 BC, and was succeeded by his son Duke Xiang of Jin; his son also inherited the hegemony, which would stay with Jin for nearly a century. Legends Ordering the Army to Retreat Three She When Chong'er stayed at the court of Chu, its king set banquets for him and afforded him good