By the beginning of the Ptolemaic dynasty, the Pyramids of Giza were already some 2200 years old. Significant cultural differences separated the Hellenistic Ptolemies from the Old Kingdom.
Were the Ptolemies still able to accurately date the Pyramids (did they even know who built them)? That is, would Ptolemy I have been able to say that the Great Pyramid was completed by Pharaoh Khufu, 2237 years before he himself became king?