Qin Mugong 秦穆公, also called Miaogong 繆公 (r. 659-621) was a ruler of the state of Qin during the Spring and Autumn period 春秋 (770-5th cent. BCE). He is sometimes counted as one of the so-called five hegemons (wuba 五霸).
His personal name was Ying Renhao 嬴任好, and he was a minor son of duke De 秦德公 (r. 677-676). He followed his brother, Duke Cheng 秦成公 (r. 663-660), to the throne. The Duke made use of the advises of Baili Xi 百里奚 and Jian Shu 蹇叔 to strengthen the state of Qin. From the beginning, Duke Mu campaigned against the east to gain a better foothold towards the Yellow River plane. He defeated the army of the state of Jin 晉 at Hequ 河曲, but then took over the protection of Jin by guiding back prince Yiwu 夷吾 to Jin, who was, with the help of Qin, enthroned as the duke of Jin, known as Duke Hui 晉惠公 (r. 650-637).ü>
When Duke Hui of Jin rebelled against his protector, the forces of Qin defeated him at Hanyuan 韓原 (modern Jishan 稷山, Shanxi). The duke was captured and only released after he ceded some territory to Qin. But Qin also won some more territory by military occupation. The peaceful state was again restored, and Qin supported prince Chong'er 重耳 to mount the throne of Jin (Duke Wen 晉文公, r. 636-628) and to put down rebellions against his rulership.
The continuing successes against the weaker state of Jin made duke Mu overconfident. In spite of Jian Shu's warnings not to undertake further campaigns with the target to conquer the small state of Zheng 鄭, the duke continued waging war in the east. Only when the army of Qin was ambushed and defeated by forces of Jin, he reoriented his targets to the west. Duke Mu could defeat the western Rong barbarians 西戎, a success to which the king of Zhou 周 sent his congratulations.