郑注
It is not known when Zheng Zhu was born. His family name was originally Yu, but he changed his name to Zheng at some point. He was skilled in medicine, and with his skills, he was able to associate with the powerful people in the Tang Dynasty capital Chang'an. (As Yu means "fish" in Chinese, eventually, when Zheng became powerful, he was sometimes obliquely referred to as "the one from the water.")