[2] It is known that he was not a member of the more prominent branches of the Zheng family that had served as officials since Northern Wei, but was from Cang Prefecture (滄州, roughly modern Cangzhou, Hebei).
Although Your Highness pleases the will of the Son of Heaven, but the five of them wield power as generals and chancellors, and their boldness and strategies exceed the common men's.
Soon, Wu Sansi and Empress Wei were able to persuade Emperor Zhongzong to remove the coup leaders from their chancellor posts under guise of honoring them with princely titles.
Wu Sansi then had accusations about his affair with Empress Wei publicly posted in Luoyang, hoping to incense Emperor Zhongzong and then blame the coup leaders.
Emperor Zhongzong denied the request, but exiled the coup leaders to even more distant prefectures, where they subsequently died or were killed on Wu Sansi's orders.
In 709, Zheng was made the minister of civil service affairs (吏部尚書, Libu Shangshu), and given the designation of Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor de facto.
After intercession by Emperor Zhongzong's concubine Consort Shangguan Wan'er, as well as Li Guo'er and Li Guo'er's new husband Wu Yanxiu (武延秀), Cui was instead made the prefect of Xiang Prefecture (襄州, roughly modern Xiangfan, Hubei), and Zheng was made the military advisor to the prefect of Jiang Prefecture.
However, later in the year, when Emperor Zhongzong was set to make sacrifices to heaven and earth south of Chang'an, he recalled both Cui and Zheng to attend to him during the ceremony and apparently made deputy minister of civil service affairs (吏部侍郎, Libu Shilang).
For reasons lost to history, she demoted Zheng Yin out of the capital, back to being the military advisor to the prefect of Jiang Prefecture.
While he went through Jun Prefecture (均州, in modern Shiyan, Hubei), he secretly discussed with Emperor Zhongzong's son Li Chongfu the Prince of Qiao, the prefect of Jun Prefecture, whom Emperor Zhongzong had disfavored and exiled, and Zhang Lingjun (張靈均), about rising in rebellion against Empress Dowager Wei.