Ptolemy III Euergetes
Demetrius’ maternal grandparents were the first Greek-Egyptian pharaoh Ptolemy I Soter and Eurydice. Among his maternal aunts were Queen Arsinoe II of Egypt and among his maternal uncles were Pharaoh Ptolemy II Philadelphus and Macedonian King Ptolemy Keraunos (Keraunos was Ptolemais’ full blooded brother). Pharaoh Ptolemy III Euergetes was a maternal cousin. His paternal grandparents were Macedonian king Antigonus I Monophthalmus and Stratonice, while his paternal uncle was the general Philip.