During the Zheng Period of the Tang Dynasty (627-649), Wei Zheng was conferred by Emperor Tai Zong the titles of the Left Grand Councilor and Duke of the State of Zheng for his dedication and valuable service in founding the Tang Dynasty. Indeed Wei Zheng was a man of great integrity and did not seek corrupt pleasure as many officials did. Wei refused to take any concubines or forsake his first wife. He also rejected the life of privilege, wealth and luxury, which many lesser men had greedily embraced after their rise in the social hierarchy.
Emperor Tai Zong decided to test Wei Zheng"s fidelity. One day, after attending court, he invited Wei Zheng to stay behind and offered him some beautiful maidens to be his concubines. Wei immediately declined the offer. The emperor pressed his offer but Wei stuck to his position. During their conversation a third voice was heard, "Please Your Majesty, will you give me the concubines, since elder brother Wei does not want them?" pleaded Cheng Yaojin, a boisterous general in the founding period. The Emperor was enraged by this insolence,and he curtly instructed Cheng to leave the court and to mind his own business.
Cheng was infuriated and rushed to the residence of the Duke of Zheng to tell Madam Wei put on her court dress and went to see the Emperor with Cheng Yaojin. She asked the Emperor to give her a reason as to why he should want to break up her happy and loving marriage. Madam Wei declared that if the emperor forced duke of Zheng to adopt concubines, she would die.The Emperor responded, "Very well then, you shall have your way." He then asked his eunuch to bring in a bottle of poisonous wine which he had mixed himself for Madam Wei to drink. Cheng Yaojin feared that the Emperor would really poison her. He tried to divert Madam Wei"s fate and purposefully bumped into the eunuch carrying the bottle of poisoned wine which broke into pieces. Chen then replaced the broken bottle with a bottle of vinegar. The eunuch handed it to Madam Wei and she drank it in one gulp. She then waited to die but nothing happened, except for the strong acidic taste in her mouth. Cheng Yaojin then remarked that it was remarkable Madam Wei could drink so much vinegar. The Emperor was as confused as Madam Wei and asked the eunuch to explain what was going on. The Emperor smiled at the antics but remarked that it was a shame to have wasted the "poisonous" hundred flower juice he had personally prepared. Actually the Emperor did not really intend to poison Madam Wei, he was merely amused to see how far her love would go.
Cheng Yaojin"s credulousness and replacement of the hundred flower juice with vinegar has become a story with meaning for many jealous lovers. Madam Wei"s faithful love was so strong that she would even drink poison to defend it. But over the generations it has become a vulgar adage which means being jealous of a rival in love.