See biographies by J. Lindsay (1971) and M. Grant (1973); J. Samson, Nefertiti and Cleopatra: Queen-Monarchs of Ancient Egypt (1987).
Ptolemy Philadelphus (ο Πτολεμαίος Φιλάδελφος), August/September 36 BC - 29 BC) was a Ptolemaic Prince and was the youngest child of Greek Ptolemaic Queen Cleopatra VII of Egypt and Roman Triumvir Mark Antony. Ptolemy was of Greek and Roman heritage. He was born in Antioch, Syria (this part of ancient Syria, is now apart of modern Turkey). Ptolemy was named after the original Ptolemy II Philadelphus (the second Pharaoh of the Ptolemaic dynasty) and Cleopatra’s intention was recreating the former Ptolemaic Kingdom. In late 34 BC, at the Donations of Alexandria, Ptolemy was made ruler of Syria, Phoenicia and Cilicia.
His parents were defeated by Octavian (future Roman Emperor Augustus) during the naval battle at Actium, Greece in 31 BC. The next year, his parents committed suicide as Octavian and his army invaded Egypt.
Octavian took him and elder siblings Alexander Helios and Cleopatra Selene II from Egypt to Italy. The three children became orphans. Octavian celebrated his military triumph in Rome, by parading the three orphans in heavy golden chains in the streets of Rome. The chains were so heavy, they could not walk. The three siblings were taken by Octavian and given to Octavia Minor to be raised in her house in Rome. Octavia Minor became their guardian, was Octavian’s second elder sister and was their father’s former wife.
The fate of Ptolemy Philadelphus is unknown. Plutarch states that the only child that Octavian killed out of Antony’s children was Marcus Antonius Antyllus. The ancient sources do not mention any military service, political career, if he was involved in any scandals, any marriage plans or any descendants and if he survived to adulthood, it would have been mentioned. Ptolemy probably died from illness in the Winter of 29 BC, but this is not sure.