By the end of 5th century BC, China was in the Warring States period in which seven prominent states sometimes battles each other and sometimes made alliance.
One year, the state of Wei allied with the state of Zhao. According to the then custom, the two states had to exchange princes as hostages. Pang Cong, the minister of Wei, was ordered to accompany the prince of Wei to go to Zhao. He was worried that his political opponents would speak ill of him while he was away.
So he came to the king of Wei, saying, "Your Majesty, if someone were to tell you that there was a tiger running in the street, would you believe it?"
"If two people were to tell you there was a tiger running in the street, would Your Majesty believe it? "
"I might suspect it, " the king said hesitatingly, "but normally I wouldn't believe it. "
"What if three people were to tell you that?"
After thinking for a while, the king said, "Yes, I would."
Pang Cong said, "Your Majesty, it is for sure no tiger is running in the street. But after being told by three people that there was one, you would believe it was so. Now I'm going to Han Dan (the capital of Zhao) far away from Da Liang (the capital of Wei). There will certainly be more than three people speaking ill of me in front of you, I wish Your Majesty would give it your mature consideration."
The king said, "Good, I would."
However, after Pang Cong leaving, the king believed the slanderous gossips about him and no longer trusted him.
Background and Writer Comment:
This Chinese idiom story is from "This story is from Intrigues of the Warring States" (战国策, Zhan Guo Ce).
The idiom of Three People Make A Tiger--San Ren Cheng Hu is used to describe the case in which a lie, if repeated often enough, will be accepted as truth. Its English counterpart is "It must be true that all men say".