Emperor Wu of Liang, Xiao Yan, reigned for 48 years over a peaceful, war-free realm. He worked tirelessly to secure his rule, but his foolish greed led to a fatal blunder: in his old age, he accepted the surrender of Hou Jing from the Eastern Wei, luring a wolf into the house. This sparked Hou Jing's rebellion, which sacked the capital, followed by a brutal scramble for the throne among the emperor's sons and nephews, devastating society. In short, Emperor Wu himself brewed the chaos.
Emperor Wu of Liang's maternal uncle, Zhang Hongji, had a son named Zhang Zan. Zhang Hongji arranged a marriage alliance with the emperor, betrothing Zhang Zan to the emperor's fourth daughter, Princess Fuyang. This made Zhang Zan both the emperor's cousin and son-in-law, a uniquely privileged position. Emperor Wu of Liang greatly valued Zhang Zan, appointing him to numerous high-ranking posts.
Zhang Zan was a man of integrity, strong character, and sharp insight. When he served as Minister of Personnel, he often defied the fierce objections of powerful nobles, boldly promoting talented individuals from humble and impoverished backgrounds, yet he refused to curry favor with Emperor Wu of Liang's own sons.
Later, Zhang Zan was promoted to Chijie (imperial commissioner with special authority), overseeing the military affairs of Xiang, Gui, and Dongning provinces while concurrently serving as the governor of Xiang Province. During his tenure, he frequently conducted personal inspections and visits to subordinate counties, releasing elderly and ailing officials and soldiers from government offices to return home for rest. He boldly streamlined the bureaucracy, cutting redundant positions, which significantly boosted administrative efficiency. Within just a few years, Xiang Province achieved harmonious governance and smooth operations; those who had fled due to hardship gradually returned, increasing the registered population by over one hundred thousand, and society became remarkably stable.
However, Zhang Zan's arrogance and disdain for others, especially his disrespect toward several young princes (his grand-nephews), incurred their resentment. He was ultimately killed by soldiers under Prince Xiao Cha of Yueyang (son of Crown Prince Xiao Tong) at the age of just 51.
Among the princes, Zhang Zan only found Xiao Yi agreeable to talk with, often engaging in spirited and endless discussions, sometimes from morning till night without tiring. Xiao Yi later defeated all his rivals and ascended the throne as Emperor Yuan of Liang, posthumously honoring Zhang Zan as "Duke Jianxian."
Emperor Yuan of Liang once wrote a poem in memory of Zhang Zan, and in its preface, he recalled how Zhang Zan, though arrogant and dismissive toward other princes, would spend entire days and nights talking tirelessly with him, Xiao Yi, without ever growing weary. The emperor lamented, 'This man's virtue and talent are truly unforgettable,' revealing his boundless longing for the prematurely departed Zhang Zan.
In the idiom "Shen Dan Da Xi," "shen" means "to reach," describing from night to morning and morning to evening, signifying ceaseless day and night.
Source: *Book of Liang*, "Biography of Zhang Zan"
Meaning of the Idiom: Later, the Chinese idiom "申旦达夕" came to describe how from night to morning and morning to evening, signifying ceaseless day and night.