A more thorough explanation:

The ancient document rule is a way to prove the authenticity of evidence in court. According to this rule, if a document is:

1. More than 20 years old
2. Looks normal and hasn't been changed
3. Found in a place where it would be expected to be found

Then the document is considered to be authentic and can be used as evidence in court.

For example, let's say a lawyer wants to use a letter that was written by someone who has since passed away. If the letter is more than 20 years old, looks normal, and was found in a place where it would be expected to be found (like in the person's old desk), then it can be used as evidence in court.

The ancient document rule can also be used as a hearsay exception under Federal Rule of Evidence 803 (16). This means that if a document is more than 20 years old and was created before 1998, it can be used as evidence even if it contains hearsay (secondhand information).

For example, let's say a lawyer wants to use a diary entry from someone who has since passed away. If the diary entry is more than 20 years old, was created before 1998, and was found in a place where it would be expected to be found (like in the person's old bedroom), then it can be used as evidence in court even if it contains hearsay.

Overall, the ancient document rule is a way to prove the authenticity of old documents in court, making them admissible as evidence.