Han Xin, a native of Huaiyin, was poor and lacked a good reputation in his youth, unable to secure an official post or make a living through trade, so he often mooched meals from others, earning widespread disdain.
Han Xin was fishing under the city wall when an old woman washing silk noticed he was hungry and gave him food. Delighted, Han Xin said to her, "I will surely repay you handsomely."
In Huaiyin, a young butcher's apprentice insulted the general Han Xin, saying, "You may be tall and carry a sword, but you're nothing but a coward." Then, publicly humiliating him, he added, "If you're not afraid to die, stab me now; if you are, crawl between my legs." Han Xin studied the man carefully, then lowered himself to the ground and crawled through his legs.
Later, Han Xin pledged allegiance to Liu Bang, the King of Han, and had the chance to speak with Liu Bang's prime minister, Xiao He. Xiao He recognized Han Xin as an extraordinary talent. Han Xin assumed Xiao He would recommend him to the king, but when Liu Bang still didn't appoint him to any post, Han Xin fled. Upon hearing of Han Xin's escape, Xiao He rushed after him without even reporting to the king, eventually tracking him down and bringing him back.
Emperor Gaozu of Han blamed Xiao He, who replied, "A talent as exceptional as Han Xin is unmatched in all the world." Liu Bang said, "For your sake, I'll make him a general." Xiao He said, "Even as a general, Han Xin won't stay." Liu Bang said, "Then make him Grand General."
Xiao He said, "If Your Majesty is determined to appoint him, you must choose an auspicious day, fast in person, set up a high altar and a grand square, maintain a solemn demeanor, and complete the full rites." King Liu Bang of Han agreed to Xiao He's request. After careful preparations, a dignified ceremony was held, and Han Xin was formally appointed as the Grand General.
After Han Xin became the Grand General, he led his army to many victories and rendered great service to the Han Dynasty.
Later, the idiom "Building an Altar and Appointing a General" came to describe appointing someone as a military commander.
Source: *Records of the Grand Historian*, "Biography of the Marquis of Huaiyin"
Meaning of the Idiom: Later, the Chinese idiom "筑坛拜将" came to describe appointing someone as a military commander.