During the late Eastern Han Dynasty, Cao Cao crushed the main forces of the northern warlord Yuan Shao at the Battle of Guandu, laying the foundation for unifying the north. In 204 AD, to completely eliminate the Yuan family's separatist power, Cao Cao led his army to attack their stronghold, Ye City, with his 18-year-old son Cao Pi accompanying the campaign.
After the capture of Ye City, Cao Pi led his troops into Yuan Shao's mansion. Seeing that Yuan Xi's wife, Lady Zhen, was exceptionally beautiful, Cao Pi took her as his wife. Cao Cao, upon seeing Lady Zhen's beauty, remarked, "She is truly a worthy wife for my son!"
After that, Cao Pi settled in Ye City and lived there for over a decade. A man of literary brilliance, he attracted a circle of scholars around him, including the renowned Kong Rong, Wang Can, and Chen Lin.
Kong Rong, the 20th-generation descendant of Confucius, was known for his extraordinary intelligence as a child. One day, his family gathered to eat pears, and he chose the smallest one. When the adults asked why, he replied, "The bigger pears should go to the elders. I am the youngest, so I should take the smallest." This story illustrates the virtue of humility and respect for elders, often cited today to praise selfless and considerate behavior.
When Cao Pi married Lady Zhen, Kong Rong was in Ye City. Learning of this, Kong Rong wrote to Cao Cao, claiming that when King Wu of Zhou conquered King Zhou of Shang, he gave the favored concubine Daji to the Duke of Zhou.
Cao Cao read the letter but did not immediately grasp its meaning. Later, when Cao Cao met Kong Rong, he asked him what historical source there was for King Wu awarding Daji to the Duke of Zhou. Kong Rong smiled and replied:
"This is merely my inference based on the prince's marriage to Lady Zhen—just a guess."
Cao Cao heard this and could only chuckle to himself.
Later, the idiom "taking it for granted" came to describe treating subjective assumptions as facts, even when they don't match reality.
Source: *Book of the Later Han*, Chapter "Biography of Kong Rong"
Meaning of the Idiom: Later, the Chinese idiom "想当然" came to describe how treating subjective assumptions as facts, even when they don't match reality.