Holding the Ox's Ear: In ancient times, princes made an alliance, requiring each person to taste a bite of the blood of a sacrifice. Those who made the alliance would personally cut the cow's ear to collect the blood, so "Holding the Ox's Ear" was used to refer to the leader of the alliance. "Zuo Zhuan" records: "In the alliance of princes, who is the leader?" Later, it often refers to holding a leadership position in a certain aspect. Beichen: originally refers to the North Star. "Erya" said: "The North Pole is called Beichen." It was later used to refer to the king or a respected person, and also to the imperial capital, such as Wang Bo's "Preface to the Pavilion of Prince Teng": "The terrain is extremely extreme and the southern sea is deep, the sky pillar is high and the Beichen Far.
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