After returning to Chang'an from Pei County, Liu Bang's arrow wound on his chest flared up again, and despite the physicians' efforts, his condition failed to improve. Lying on his sickbed, Liu Bang realized his injury was beyond recovery and his life was nearing its end, so he dismissed the physicians with rewards, knowing their efforts were futile. Having campaigned east and west for so many years, he felt relieved that the realm was finally in the hands of the Liu family. With the state's foundation stabilized and laws revised, his descendants could simply rely on this legacy. Yet Liu Bang grew anxious, thinking of the powerful ministers and feudal lords—all founding heroes—who might rebel; his descendants, lacking battlefield experience, would be no match for them, and the Han Dynasty could fall into others' hands.
During the conflict between Chu and Han, Liu Bang, in order to win the support of more capable people, enfeoffed many kings with different surnames. These kings fought alongside Liu Bang to conquer the realm and helped him establish the Han Dynasty. It can be said that without them, Liu Bang would never have achieved such great accomplishments, but their achievements were precisely what worried him most. If one day they were no longer content with merely being kings, relying on their formidable power and vast territories, they could overthrow the Han Dynasty at any time, and if they joined forces, the consequences would be even more severe. Were not Han Xin, Peng Yue, and Ying Bu living examples? They held high positions and great power, yet still plotted rebellion. In fact, after executing these three, Liu Bang began to enfeoff kings with the same surname, gradually replacing the kings with different surnames to consolidate the Liu family's rule. Despite taking many defensive measures, Liu Bang remained uneasy, so he decided to swear a covenant with his ministers on a white horse.
In ancient times, white horses were considered sacred animals, and using a white horse to swear an oath or form an alliance signified that both parties placed great importance on their vow and dared not break it. Liu Bang gathered his ministers together, ordered a servant to slaughter a white horse, and distributed the horse's blood to each of them. Holding the horse's blood, Liu Bang demanded that the ministers pledge to forever assist the descendants of the Liu family without any disloyal intentions, and he emphasized that no one outside the Liu family could be enfeoffed as a king, and those without merit could not be granted noble titles; if anyone violated this oath, everyone under heaven would have the right to kill them. The ministers swore eternal loyalty to the Han Dynasty and vowed to always support the Liu family's descendants. Hearing this, Liu Bang finally felt at ease.
Emperor Gaozu of Han's health deteriorated day by day, and Empress Lü watched with deep sorrow; she hoped for his recovery but knew it was nearly impossible, and if her husband died, how would the Liu family's enterprise be managed? Several times Empress Lü wanted to ask but held back, but as the emperor's illness grew more severe, she finally mustered the courage to speak: "Your Majesty, have you considered who could succeed Xiao He as Chancellor if he were to pass away?" Emperor Gaozu replied, "Cao Can can take his place." Empress Lü then asked, "And if Cao Can also dies?" The emperor said, "Wang Ling can serve. Although Wang Ling's wisdom is not as great as Cao Can's, his upright character is commendable; let him manage state affairs together with Chen Ping. Chen Ping excels in many areas, but he lacks flexibility in critical moments and often needs guidance from others. Zhou Bo should be promoted to Grand Commandant; though he may not be as clever as others, his loyalty and honesty are unmatched, and he always prioritizes the greater good, balancing gains and losses with the best judgment—with him, the Han Dynasty will surely remain stable."
After saying this, Liu Bang was gasping for breath. Empress Lü wanted to ask more questions, but seeing that he couldn't speak after several attempts to catch his breath, she had to stop. Liu Bang knew what else she wanted to ask and, mustering all his strength, said haltingly, "What happens after that, no one can know." Hearing this, Empress Lü couldn't hold back her tears.
In 195 BCE, on the twenty-fifth day of the fourth month of the twelfth year of his reign, Emperor Gaozu of Han, Liu Bang, passed away. He was posthumously honored as Emperor Gao, with the temple name Taizu, and was buried in Changling. In the same year, Crown Prince Liu Ying ascended the throne, historically known as Emperor Hui of Han, and he continued to appoint Xiao He as Chancellor.
Liu Bang was the first emperor in Chinese history to ascend the throne from commoner status, and also the first to personally lead military campaigns and unify the realm. After his coronation, he launched campaigns against the Xiongnu in the north, suppressed rebellions, and allowed the people to recuperate and rebuild, which rapidly restored and developed social productivity. His contributions to the unification of the Han ethnic group, the unification of China, and the protection of Han culture are immeasurable.