It is not known when the future Empress Dowager Zheng was born, and little is known about her family. According to the Old Book of Tang, at the time that that history was compiled, the old records were missing as to her family origins or how she entered the palace. However, according to the New Book of Tang, she was from Danyang, and her surname might have been originally Erzhu. Further according to the New Book of Tang, early in the Yuanhe era of Emperor Xianzong, when her home region was ruled by the military governorLi Qi, a fortuneteller prophesied that she would give birth to an emperor. Hearing this, Li Qi decided to take her as a concubine. After Li Qi was defeated and executed in 807, she was confiscated and taken into the imperial palace, where she became a servant girl of Emperor Xianzong's wife Consort Guo.
At some point, Emperor Xianzong had sexual relations with Lady Zheng, and she gave birth to the 13th of his 20 sons, Li Yi. It was implied by the Old Book of Tang that she was then made an imperial consort with the relatively low rank of Yunü.
As consort dowager
Emperor Xianzong died in 820, and his son by Consort Guo, Li Heng became emperor. In 821, he created a number of his brothers princes, and it was at that time that Li Yi was created the Prince of Guang. Consort Zheng thus became Consort Dowager of Guang. Her activities during this time were not recorded in history, although it was said that, in 846, her younger brother Zheng Guang dreamed of a wagon bearing the sun and the moon, and six lighted candles uniting into one. A fortune teller informed him that this was a sign of great fortune to come.
As empress dowager
Later in 846, Li Yi's nephew Emperor Wuzong was seriously ill, and the powerful eunuchs inside the palace, believing that Li Yi would be easily controlled, issued an edict in Emperor Wuzong's name creating Li Yi crown prince and renaming him to Li Chen. When Emperor Wuzong died shortly thereafter, Li Chen became emperor. He honored Consort Dowager Zheng as an empress dowager. Zheng Guang, on account of his being Empress Dowager Zheng's brother, was initially made a general, and then the military governor of Pinglu Circuit. In 848, Grand Empress Dowager Guo died — purportedly murdered by Emperor Xuānzong. Empress Dowager Zheng had long resented Grand Empress Dowager Guo from the days when she was a servant girl under then-Consort Guo. It was said that because of this, and because Emperor Xuānzong suspected Grand Empress Dowager Guo of being complicit in Emperor Xianzong's suspicious death, Emperor Xuānzong did not accord Grand Empress Dowager Guo great respect, causing her to be distressed, almost committing suicide. On one occasion, she nearly jumped off a tower, and it was said that Emperor Xuānzong was greatly displeased and had her murdered. Emperor Xuānzong eventually wanted to allow his mother to be buried with his father Emperor Xianzong, and so initially, he would not let Grand Empress Dowager Guo be buried with Emperor Xianzong. However, after a controversy erupted, he relented. It was said that Emperor Xuānzong served his mother in a filially pious way, and because she did not want to reside anywhere else, she remained at his Daming Palace. Also because of her, after Zheng Guang served as military governor of Pinglu, Zheng Guang was given another term as military governor of Hezhong Circuit. On an occasion when Zheng Guang was at the capital Chang'an to give homage to Emperor Xuānzong, however, Emperor Xuānzong asked him for advice and was distressed to hear what he thought to be unworthy responses. He kept Zheng Guang at Chang'an, giving him a general title. Empress Dowager Zheng repeatedly told him that Zheng Guang was poor, and the emperor responded by awarding Zheng Guang great wealth, but did not again allow Zheng Guang to govern the people.
Emperor Xuānzong died in 859 and was succeeded by his son Li Cui. Emperor Yizong honored Empress Dowager Zheng as grand empress dowager. She died in 865. As Empress Dowager Guo was already buried with Emperor Xianzong and enshrined at his temple, she was neither; rather, she was buried near Emperor Xianzong's tomb and enshrined in a separate temple.
