Shang influence by the thirteenth century BCE…

Shang influence by the thirteenth century BCE reached what is now Gansu Province, a region occupied by a people known as the Zhou.

King Wen of Zhou (Ji Chang), the ruler of the Zhou, who is a Shang vassal, had been given the title "Count of the West" by King Di Xin of Shang (King Zhou), who used Duke Wen to guard his rear while he was involved in a southeastern campaign.

Eventually, Di Xin, fearing Duke Wen's growing power, had imprisoned him.

Although Wen had later been released, the tension between Shang and Zhou has continued to grow.

Wen prepared his army, and has conquered a few smaller loyal states to Shang, slowly weakening Shang's allies.

However, Duke Wen dies in 1050 BCE before Zhou's actual offense against Shang.