What is the earliest existing celebrity calligraphy ink?

Reply to the post. According to the inquiry of China Calligraphers Association official website, the Reply Post consists of 9 lines and 84 words. Written in the Western Jin Dynasty, it is the earliest calligraphy post handed down by famous artists and the first orderly calligraphy post in history. Enjoy the reputation of "calligraphy sticks to the ancestors" and be rated as "the treasure of the town and the country".