Which dynasty is the legend of Zheng Kaizhi?

There seems to be no such person in history. In the Eastern Jin Dynasty, there was a Gu Kaizhi (348-409), whose long character was Kang and small character was Tiger Head, Han nationality, a native of Wuxi, and a native of Jinling (now Jiaoxi, Jiangsu). Gu Kaizhi is knowledgeable and talented. He is good at poetry and calligraphy, especially painting. Specializing in portraits, Buddha statues, animals, landscapes, etc. People call it the three musts: painting, writing and infatuation. Xie Anshen was impressed, born without it. Gu Kaizhi, Cao Buxing, Lu Tanwei and Zhang Sengyou are also called "Four Masters in Six Dynasties". Gu Kaizhi's painting intention is vivid, and his ideas of "moving the mind" and "describing the spirit with form" laid the foundation for the development of traditional painting in China.