History, taught by the official He Chengtian () Literature, taught by the official Xie Yuan () Confucianism, taught by the hermit Lei Cizong () The historian Sima Guang, author of Zizhi Tongjian, made the following commentary about Emperor Wen with regard to the status of his state at this time: Emperor Wen's attention to imperial officials' abilities could be seen partly in 439, when, according to an edict that Emperor Wu had left that his sons were to serve as the governor of Jing Province in rotation by age, he was supposed to make his brother Liu Yixuan () the Prince of Nanqiao the governor of Jing Province. However, because he believed Liu Yixuan to be incompetent, he refused, skipping him and giving the post to the more capable brother Liu Yiji () the Prince of Hengyang, the governor of Jing Province. (Several years later, after Liu Yiji's death, and with much urging from his older sister Liu Xingdi () the Princess Kuaiji, he finally did make Liu Yixuan the governor of Jing Province, but only after much advice on how to properly govern the province.) By 440, however, Liu Yikang, a major part of the success of Emperor Wen's government due to his diligence and abilities, had become so flattered by Liu Zhan that he appeared to blur the distinction between himself, as a subject, and the emperor. When Emperor Wen grew ill again, Liu Zhan and Liu Yikang's associates Liu Bin (), Wang Lü (), Liu Jingwen (), and Kong Yinxiu () secretly plotted to have Liu Yikang succeed Emperor Wen, against Emperor Wen's wishes to have Crown Prince Shao be emperor and Liu Yikang serve as regent. When Emperor Wen grew better, he began to suspect Liu Yikang of wanting to usurp the throne. In winter 440, he put Liu Yikang under house arrest, while arresting and executing Liu Zhan and a number of other associates of Liu Yikang. He then removed Liu Yikang from his prime minister post and made him the governor of Jiang Province, while restoring Yin Jingren to power. He replaced Liu Yikang with another younger brother, Liu Yigong () the Prince of Jiangxia, but Liu Yigong, realizing the danger in wielding too much power, did not involve himself much in actual decision-making. Later that year, Yin Jingren died, and the important responsibilities became split between several officials. In 441, Yang Nandang, not