Simplify the following text for a Grade 8 native English-speaking person.
Original: Hattusili and the Egyptian pharaoh Ramesses II sealed a written peace treaty based upon Hittite models which , due to Egyptian monumental copies of it , has become the earliest well known treaty in history , establishing a long-lasting peace between the two rival empires .
Simplified: Hattusili and the Egyptian pharaoh Ramesses II later made a peace treaty .