A more thorough explanation:

in cujus rei testimonium

In cujus rei testimonium is a Latin phrase that means "in witness whereof." It was commonly used in legal documents, such as deeds, to indicate that the document was being signed as evidence of a transaction or agreement.

Example 1: "In cujus rei testimonium, we have hereunto set our hands and seals."

Example 2: "This agreement is made in cujus rei testimonium of the parties' mutual understanding and agreement."

These examples show how the phrase "in cujus rei testimonium" was used to conclude legal documents and indicate that the parties involved were signing the document as evidence of their agreement or transaction.