Duke Xiao is best known for employing the Legalist statesman Shang Yang[1] from the Wey state and authorizing him to conduct a series of ground breaking political, military and economic reforms in Qin.
Hence, the duke sent out an announcement, calling for men of talent to aid him in strengthening Qin, promising them rewards of high offices and lands in return for their service.
[5] In 366 BC, the Qin armies defeated the allied forces from the states of Han and Wei at the Battle of Shimen.
[6] The Qin soldiers and officers were promoted to higher ranks based on the number of enemy heads they collected during battle.
The change was an indication of the loss of authority of the central government (Zhou dynasty), as rulers of several other feudal states had begun to call themselves "kings" instead of "dukes".