In 1368, Zhu Yuanzhang became emperor and firmly controlled the military and political power in his own hands.

From 1370 to 1391, he made 23 of his 26 sons princes three times and sent them to various strategic locations across the country.

Zhu Yuanzhang stipulated that princes stationed in various places were not allowed to interfere with local civil affairs. As the emperor's representatives in local military power, they were the monitors of the local garrison forces and held the local military command power.

In 1370, Zhu Yuanzhang's fourth son Zhu Di was granted the title of King Yan.

In 1378, Zhu Yuanzhang changed Nanjing to the capital and let the princes be assigned to their respective fiefs one after another.

On April 16, 1380 (March 11, the 13th year of Ming Hongwu), King Zhu Di of Yan officially went to his fief, Peiping. Because Peiping was responsible for defending against the invasion of Mongol nobles, Zhu Yuanzhang gave him more troops than other princes, and allowed him to decide on small matters in the army, except for major matters, which greatly enhanced Zhu Di's strength.