Simplify the following text for a Grade 9 native English-speaking person.
Original: It is mentioned in Chinese writings dating back nearly 3,000 years , and related instruments have been found in Tomb of Marquis Yi of Zeng from about 2,500 years ago .
Simplified: It is mentioned in Chinese writings dating back nearly 3,000 years , and related instruments have been found in tombs from about 2,500 years ago .