He belonged to the Orontid dynasty, founded by Orontes I. Ptolemaeus' father was King Orontes IV of Armenia, son of Arsames I. Ptolemaeus was the last satrap (governor) of the state of Commagene, a province in the Seleucid Empire.
When the Seleucid Empire began to disintegrate, Ptolemaeus asserted his sovereignty and made Commagene an independent kingdom in 163 BC.
Also, according to fragments of inscribed reliefs found at Mount Nemrut, archaeologists have discovered that Ptolemaeus was a descendant of King Darius I of Persia.
His son and successor was Sames II Theosebes Dikaios.
This biography of a member of a Middle Eastern royal house is a stub.