In 1424, Emperor Zhu Di, leading a campaign against the remaining Mongol forces in the north, passed away in his military camp. At that moment, his eldest son, Zhu Gaochi, was the designated successor according to imperial rituals. However, the situation was far more complicated than it seemed. Zhu Gaochi’s younger brother, Zhu Gaoxu, not only wielded military power in his own domain but had also received a verbal promise from Zhu Di to inherit the throne. If the news of Zhu Di's death was not handled carefully, it could quickly lead to a deadly internal conflict within the Ming dynasty. Fortunately, the court official Yang Rong, who accompanied the army, acted swiftly by sealing off the information and sending fast riders back to the capital, urging Zhu Gaochi to ascend the throne as per Zhu Di’s last will.
During the Jingnan campaign, Zhu Gaoxu had not only earned many military accolades but had even saved Zhu Di’s life on several occasions. In his gratitude, Zhu Di promised Zhu Gaoxu that, once he passed, the throne would be his. But once Zhu Di ascended the throne, the political landscape shifted dramatically. Court officials rallied behind Zhu Gaochi, the rightful heir, and with their constant advice, Zhu Di’s confidence wavered. Changing the heir could disrupt the very foundations of the empire, leading people to question the validity of Ming law. Moreover, the shift in succession could set a dangerous precedent, potentially causing Zhu Gaochi’s own brothers, or even Zhu Di’s other relatives, to follow his example and rebel. In the end, Zhu Di reneged on his promise and confirmed Zhu Gaochi as his successor.
To prevent another bloody family conflict, Zhu Di appointed Zhu Gaoxu as the King of Han and stationed him in the far-off province of Shandong, limiting his power to some extent. Despite this, Zhu Gaoxu continued to hold disdain for his elder brother, Zhu Gaochi, and harbored resentment towards his father for breaking his word. However, the ruler of the empire was still the decisive and ruthless Zhu Di, and Zhu Gaoxu dared not openly rebel. When Zhu Gaochi eventually ascended the throne, Zhu Gaoxu, already brimming with ambitions, considered revolting. But he was aware that Zhu Gaochi had won the support of the people due to his benevolent governance. Unable to match his brother’s popularity and strength, Zhu Gaoxu had to suppress his desire for rebellion, biding his time.
In 1415, the aging Zhu Di made another startling decision by naming Zhu Gaochi’s son, Zhu Zhanji, as the heir apparent. This was a clear sign that Zhu Di intended the throne to pass smoothly through the line of Zhu Gaochi. At the same time, it served as a warning to Zhu Gaoxu: accept your position as a regional prince and abandon your thoughts of the throne. Little did Zhu Di know, not long after Zhu Gaochi’s succession, he would fall ill and die unexpectedly. When Zhu Gaoxu received news of his elder brother’s death, years of suppressed ambition surged within him. With Zhu Zhanji preparing to travel to Nanjing for the coronation, Zhu Gaoxu secretly arranged an attempt on his life. However, the plot failed, and Zhu Zhanji reached Nanjing without incident to claim the throne.
To placate the ambitious uncles and prevent further discord, Zhu Zhanji rewarded them with generous titles and increased stipends. It was clear that he was prepared for possible rebellion from Zhu Gaoxu, yet hoped to quell his ambitions with gifts. But for Zhu Gaoxu, the memories of his father’s own revolt against Emperor Yongle were still fresh. Like his father, he commanded a strong military and was just as capable of taking bold actions. Why should he not follow in his father’s footsteps and seize the throne from his nephew, Zhu Zhanji? In 1426, Zhu Gaoxu rebelled, citing the removal of his trusted minister, Xia Yuanji, as his reason for uprising, a pretext eerily similar to the one his father had used. Both Zhu Di and Zhu Gaoxu cloaked their rebellious actions under the banner of eliminating corrupt officials, yet they were ultimately after power.
At this time, Zhu Zhanji had already gained military experience from participating in his father’s northern campaigns. When Zhu Gaoxu plotted his rebellion, he sought to enlist the support of key officials, including the Duke of Ying, Zhang Fu. However, Zhang Fu, loyal to Zhu Zhanji, warned him of Zhu Gaoxu’s plans. Despite receiving confirmation of the rebellion, Zhu Zhanji, unlike his weak predecessor, Emperor Jianwen, was not willing to avoid confrontation. Rather than engage in open battle, he sent emissaries to persuade Zhu Gaoxu to surrender peacefully. Yet, Zhu Gaoxu, in a defiant response, criticized Zhu Zhanji for attempting to appease him with rewards. He said, “My father lost power because he trusted unworthy men. Now, you try to appease me with gifts while letting corrupt officials continue to rule.” He demanded that Zhu Zhanji himself come to meet him, a challenge the emperor could not ignore.
When the messenger returned with Zhu Gaoxu’s response, Zhang Fu suggested that with enough soldiers, he could easily capture the rebellious uncle. However, advisors like Yang Rong urged Zhu Zhanji to take caution and not repeat the mistakes of the Jianwen era. Instead, Zhu Zhanji decided to lead the army personally and quell the rebellion. He gathered his forces, marching to meet Zhu Gaoxu head-on. Despite Zhu Gaoxu’s strong military backing, he was swiftly defeated. After his capture, Zhu Zhanji deposed Zhu Gaoxu, reducing him to commoner status and imprisoning him.
While Zhu Zhanji spared his uncle, he dealt ruthlessly with the 2,700 rebels who had joined Zhu Gaoxu. Over five hundred were executed, and two thousand were exiled. This purging of Zhu Gaoxu’s supporters only fueled his hatred towards his nephew. In a fit of rage during an interrogation, Zhu Gaoxu managed to trip Zhu Zhanji, causing a momentary lapse in his guard. Enraged, Zhu Zhanji ordered that his uncle be executed in the most gruesome manner—boiled alive in a copper cauldron, a tragic end for a once-promising prince.