The text Zhuang zi has been changed over time, with the version we have today being shortened and rearranged by Guo Xiang in the 4th century AD. It is believed that the original text was prepared by Liu Xiang in the 1st century BC. Some scholars think a different version was made by the court of Huai nan in the 2nd century BC, but evidence suggests this may not be true. The earliest known quote from Zhuang zi is from 239 BC. Excavated bamboo slips have shown that some parts of the text were added later. The original version survived until the Tang dynasty, and lost parts have been found in earlier texts.