The state of Yan was one of the feudal states of the Zhou Dynasty, with its royal family being a branch of the Zhou royal lineage. They maintained a close relationship with the Zhou royal family and were held in high regard.
After King Wu of Zhou defeated the Shang Dynasty, he enfeoffed Ji Shi in the Yan territory, making him the first ruler of Yan, known as Duke of Yan.
Yan was an important feudal state for the Zhou royal family in ruling the northern regions, holding a high position.
When the authority of the Zhou royal family was still strong, Yan consistently possessed the most robust national strength among the northern states.
The land of Youyan was known for its courageous and impassioned warriors, and Yan was renowned for its formidable fighters, earning praise from all the states.
Subsequently, Yan expanded into the areas of Jibei and Liaoxi, annexing the state of Ji and establishing its capital in Ji. This period marked the peak of Yan's national strength and prosperity.
However, after the fall of the Zhou royal family, Yan became an enemy of other feudal states in the north.
Later, King Yi of Yan ascended the throne. Shortly after his enthronement, his erratic behavior within the state provoked a popular uprising. Although it was barely suppressed, the subsequent Zizhi Rebellion further plunged Yan into chaos.
Prince Ping and General Shi Bei, dissatisfied with King Yi of Yan's earlier misrule, jointly raised an army to attack Zizhi, but their efforts ultimately ended in failure. General Shi Bei died in the ensuing conflict, and Prince Ping was also executed.
Although King Yi of Yan managed to temporarily quell the internal strife, he was already deeply unpopular. Both Prince Ping and General Shi Bei had enjoyed high prestige within Yan.
With these two men dead in the rebellion, the people of Yan's animosity towards King Yi of Yan intensified, leading to deep internal conflicts within the state.
Minor rebellions continued to erupt.
Two years later, the neighboring state of Qi, observing Yan's inherent weakness, saw an opportunity. King Xuan of Qi, under the guise of quelling the rebellion, dispatched an army of several hundred thousand troops into Yan, intending to conquer the state in one decisive blow.
Initially, the people of Yan lacked any will to fight. Many soldiers of the Yan army were unwilling to fight for such a ruler, and the Qi army advanced rapidly, pushing Yan to the brink of annihilation.
At this juncture, the surrounding states witnessed the situation. The foremost northern power, the state of Zhao, was unwilling to allow Qi to annex Yan.
At that time, the strongest in the north was Qi, followed by Zhao, Yan, and Lu, then Zhongshan, Song, and other states. If Qi were to truly annex Yan, then Zhao and the other states would certainly not fare well.
King Wuling of Zhao supported Prince Zhi's return to the throne, establishing him as King Zhao of Yan. The states of Wei, Lu, Zhongshan, and others, unwilling to see Qi grow too powerful, all sent troops to intervene in Yan's affairs.
The Qi forces were defeated by the coalition of states and were forced to retreat, quickly relinquishing the Yan territories they had occupied.
Yan was thus restored. After recovering its lost territories, King Zhao of Yan recruited talented individuals and implemented vigorous reforms, leading Yan back to its former prosperity.
Later, King Zhao of Yan, capitalizing on the general aversion and fear of Qi among the states at the time, took the opportunity to unite with Zhao, Lu, Zhongshan, Wei, and four other states in a joint campaign against Qi.
Qi was unable to resist. Three years later, the state fell, and Yan, in turn, replaced Qi as the most powerful state in the north, becoming the leading power among the northern states.
However, it was unfortunate that Yan could only maintain such national strength during King Zhao of Yan's reign. After King Zhao of Yan passed away, Yan began its decline, never regaining its former might.