Complex sentence: The oldest of these text come from the Pyramid of Unas, the last king of the 5th Dynasty, other texts were discovered in the pyramids of the 6th Dynasty kings Pepi I, Pepi II, and Teti.
Split into simpler sentences: The oldest of these text come from the Pyramid of Unas, the last king of the 5th Dynasty. Other texts were discovered in the pyramids of the 6th Dynasty kings Pepi I, Pepi II, and Teti.