Chun was created the Prince of Guangling. In 793, he married Lady Guo, a daughter of the deceased general Guo Ai () and Emperor Daizong's daughter Princess Shengping, as his wife and princess. In 804, Li Song (Shunzong) suffered a stroke and became unable to speak. When Emperor Dezong fell gravely ill in spring 805, Li Song was unable to visit him, and Emperor Dezong, distressed over this, died soon thereafter. After Emperor Dezong's death, the eunuchs in the palace initially considered supporting another person as emperor, but due to the objections of the imperial scholars Wei Cigong () and Zheng Yin, Li Song was able to assume the throne (as Emperor Shunzong), although during Wei and Zheng's discussion with the eunuchs, the possibility of having Li Chun take the throne directly was mentioned. As Emperor Shunzong continued to be seriously ill and unable to speak, a group of his close associates—the eunuch Li Zhongyan (), his concubine Consort Niu, the imperial scholars Wang Shuwen and Wang Pi, and the chancellor Wei Zhiyi—became the key decision-makers. It was said that this group of individuals feared Li Chun for his intelligence and decisiveness, and initially, Li Chun was not created crown prince. However, the eunuchs Ju Wenzhen (), Liu Guangqi (), and Xue Yingzhen (), all of whom were favored by Emperor Dezong and who lost their power in the new regime, summoned the imperial scholars Zheng, Wei Cigong, Li Cheng, and Wang Ya to the palace to draft an edict for Emperor Shunzong creating Li Chun as crown prince, anyway. Zheng showed a piece of paper to Emperor Shunzong reading, "The Crown Prince should be the oldest son." Emperor Shunzong, who was unable to speak, nodded, and an edict was thereafter issued in late spring 805 creating Li Chun crown prince. The edict also changed Li Chun's name (from 淳 to 純—both rendered "Chun" in modern Mandarin). It was said that Wang Shunwen was so concerned about Li Chun that he was heard reading from Du Fu's poem about the Shu Han regent Zhuge Liang—"He had not even succeeded in his campaigns when he died. This often caused heroes to weep onto their collars." Wang Shuwen and Wei Zhiyi tried to see if their group could persuade Li Chun to favor their positions by having their associate Lu Zhi () serve as the attendant to Li Chun's studies. However, it