Foundation

Surviving sources trace the ruling house of Wei to the Zhou royalty: Gao, Duke of Bi (畢公高), was a son of King Wen of Zhou. His descendants took their surname, Bi, from his fief. After the destruction of Bi, Bi Wan (畢萬) escaped to Jin, where he became a courtier of Duke Xian's, accompanying his personal carriage. After a successful military expedition, Bi Wan was granted Wei, from which his own descendants then founded the house of Wei.

Spring and Autumn period

Jin's political structure was drastically changed after the slaughter of its ruling dynasty during and after the Li Ji Unrest. Afterwards, "Jin ha[d] no princely house" (晉無公卿) and its political power diffused into extended relations of the ruling family, including the Wei. In the last years of the Spring and Autumn period, the founders of Wei, Zhao, and Han joined to attack and kill the dominant house of Zhi (知) in 453 BCE, resulting in the partition of Jin. King Weilie of Zhou finally legitimized the situation in 403 BCE, when he elevated the three houses' heads to the rank of marquess (Chinese: 侯; pinyin: hóu).

Warring States Period

The state reached its apogee during the reigns of its first two rulers, Marquess Wen of Wei and Marquess Wu of Wei. The third ruler, King Hui of Wei, declared himself an independent sovereign and concentrated on economic developments, including irrigation projects at the Yellow River. Hui felt that Qin in the west was weak and their land a barren waste. He focused on conquering the well-settled eastern lands which were richer in known resources. However, a series of battles including the battle of Maling in 341 BCE checked Wei's ambitions while Qin's expansion went largely unimpeded, boosting its economy and military strength.

Early strengthening of the state of Wei resulted from adoption of Legalist reforms proposed by Li Kui (Chinese: 李悝, c. 459 – c. 395 BCE).

Defeat

Wei eventually lost the western Hexi (河西) region, a strategic area of pastoral land on the west bank of the Yellow River between the border of modern-day Shanxi and Shaanxi, to Qin. Thereafter, it remained continuously at war with Qin, requiring the capital to be moved from Anyi to Daliang. Wei surrendered to Qin in 225 BCE, after the Qin general Wang Ben diverted the Yellow River into Daliang, destroying the capital in a flood.

Notable people

• Li Kui, a Legalist philosopher and chancellor
• Yue Yang, ancestor of Yue Yi and prime minister of Zhongshan
• Pang Juan, a successful general who was defeated by Lord Mengchang of Qi and Sun Bin at the battle of Maling

Chinese legend

According to the Records of the Warring States, a king of Wei had a lover named Lord Longyang, with whom he enjoyed fishing. One day, Longyang began to weep. When questioned, Longyang said he saw his own future in how he had treated a fish. Happy to have the catch at first, Longyang had wanted to throw it back when he caught a better fish. He wept, "I am also a previously-caught fish! I will also be thrown back!" To show his fidelity to Longyang, the king declared that, "Anyone who dares to speak of other beauties will be executed along with his entire family".^[2]

Chinese astronomy

In traditional Chinese astronomy, Wei is represented by one star in the "Twelve States" asterism of the "Girl" lunar mansion of the "Black Turtle" symbol and other star in the "Left Wall" of the "Heavenly Market" enclosure. Sources differ, however, in whether those two stars are (respectively) 33 Capricorni^[3] and Delta Herculis^[4] or whether they are Chi Capricorni and Phi Capricorni.^[5]