The Ptolemaic Period is still very much considered ancient. Yes, Egyptian history goes back much further, but modern history goes ahead much longer. It was recognised during the time that the history was already so old though. There's the famous tidbit about Cleopatra (VII) living closer to the age of computers than the building of the Great Pyramid, which is true, but she still died (and effectively ended the Ptolemaic dynasty) ~2,050 years ago which was a time very much considered ancient.

Also considering the importance of the Ptolemies in Greek and Roman history, they are brought within those timeframes as well. The Ptolemies pre-date the Roman Empire and their downfall is part of the empire's rise.