Du Zhenglun - During Emperor Gaozong's Reign

During Emperor Gaozong's Reign

In 656, Du Zhenglun was serving as the deputy minister of treasury, when Emperor Taizong's son and successor Emperor Gaozong promoted him to serve as Huangmen Shilang (黃門侍郎), the deputy head of the examination bureau (門下省, Menxia Sheng). Emperor Gaozong also gave him the designation of Tong Zhongshu Menxia Sanpin (同中書門下三品), making him a chancellor de facto. Du was also created the Duke of Xiangyang. In 657, he was made Zhongshu Ling (中書令), the head of the legislative bureau and a post considered one for a chancellor. Later that year, he concurred with the official Liu Xiangdao that there were too many people made imperial officials, and Emperor Gaozong put them in charge of drafting a proposal to reduce the number of officials. However, their proposal ran into much opposition from other officials and was never carried out.

Meanwhile, Du was beginning to have conflict with fellow chancellor Li Yifu, who also carried the title of Zhongshu Ling, as Du considered himself the senior official, but Li, who was an ally of Emperor Gaozong's powerful wife Empress Wu (later known as Wu Zetian), disrespected Du. They argued frequently before Emperor Gaozong, who rebuked both for not cooperating with each other. On December 6, 658, Emperor Gaozong demoted both to be prefects—in Du's case, the prefect of Heng Prefecture (橫州, roughly modern Nanning, Guangxi). Du was said to have died at Heng Prefecture soon thereafter.