Emperor Taizu (Zhu Yuanzhang) overthrew the Yuan Dynasty and founded the Ming Dynasty. He made Nanjing the capital. In order to strengthen the frontier defense in the north, Zhu Yuanzhang made his fourth son Zhu Di the Prince of Yan and gave Beiping to him as his domain. In 1398, Zhu Yuanzhang died and his grandson Zhu Yunwen succeeded to the throne. Historically he was known as Emperor Jianwen. After he came to the throne, he deeply felt the threat from the various vassals who had powerful troops under their command. He adopted the advice of Qi Tai, Minister of War, and Huang Zicheng, Minister of the Court of Imperial Sacrifices to weaken the power of the vassals. In the 6th lunar month of the year when he came to the throne, he began to depose Prince of Zhou, Prince of Xiang and three other princes in outlying areas. Zhu Di, the Prince of Yan, who had 100,000 troops under his command, was the most powerful vassal. He launched a punitive expedition against Qi and Huang under the pretext of "no honest ministers but treacherous officials in the imperial court." He won the war to seize the throne. In 1402, he stormed into Nanjing and seized the throne. Emperor Jianwen was nowhere to be found. Qi Tai, Huang Zicheng and other senior officials as well as their families were executed. Tens of thousands of people were involved in the case and executed. In 1403, Zhu Di changed the reign title to Yongle and issued an imperial edict to "take Beiping as Beijing" (Northern Capital). He decided to move the capital. In the first lunar month of the 19th year of the reign of Yongle (1421), Beijing became the capital.

According to the established law contained in the Veritable Records of Taizu that "a big bell can be cast only for those who made meritorious services," he ordered the casting of the matchless big bell. The Yongle Bell was regarded as a "guardian" when Zhu Di moved the capital to Beijing. It was also a symbol of the greatest reverence of imperial power.

In the old days, there was another argument for the casting of the Yongle Bell. In the Ode to the Big Bell of the Temple of Awakening, Shen Deqian, a poet of the Qing Dynasty, wrote:

 "The swallow (referring to the Prince of Yah) flew to peck the boy.

          A million troops advanced southward like worms.

          Many were implicated and killed in cold blood.

          Loyal officials were eliminated in a disaster.

          The might of Buddha was relied on to wipe out the black karma.

          The bell resounded through the gates of Heaven..."

The poet denounced Zhu Di for killing innocent people without discrimination to seize the throne and pointed out explicitly that Emperor Chengzu had the bell cast to "eliminate the black karma by relying on the might of Buddha." After he read this poem, Emperor Qianlong wrote these interesting verses:

  "How tragic and vicious the implication was!

          Graves were scattered on both banks of the Longjiang.

          The pen of a historian could hardly be avoided.

          He confessed by dint of the Buddhist bell..."

In the capacity of an emperor, Qianlong noted without restraint and more incisively that in the battle to usurp the throne, Zhu Di killed countless people and cruelly implicated many others in the case and that he had the bell cast with a view to confessing by dint of the bell.

No matter which argument holds true, Emperor Chengzu has really left behind an admirable and priceless treasure. Several hundred years have elapsed. The rise and fall of emperors have gone with the wind. But the Yongle Bell remains majestic. It is a crystallization of superb skills of laboring people in ancient times. Today, the resounding strokes of the Yongle Bell spread the splendid civilization of the Chinese nation far and near.

   
Opinions are widely divided about when the Yongle Bell was cast, the casting technology, the inscriptions on the bell and the relocations of the bell. Even erroneous messages have been incorrectly relayed. The establishment of the Big Bell Temple Museum has made it possible to carry out comprehensive, thoroughgoing and systematic textual research on the Yongle Bell.