Who and when did the earliest calligraphy works exist?

Lu Ji's "Ping Fu Tie" in the Western Jin Dynasty is the earliest calligraphy work handed down by celebrities that can be recognized at present.

"Reply", paper, hand-rolled, 23.7 cm long and 20.6 cm wide; Cao Lishu has 9 lines and 86 words.

Ping Fu Tie was written more than 1700 years ago, and it is the earliest and most authentic calligraphy post of famous western Jin Dynasty. Written on hemp paper with a bald pen, the brushwork is euphemistic, the style is simple and the font is cursive. Reply posts occupy an important position in the history of calligraphy in China.