Ptolemy IV Philopator (Greek: Πτολεμαῖος Φιλοπάτωρ Ptolemaĩos Philopátōr; reigned 221–204 BC), son of Ptolemy III and Berenice II of Egypt, was the fourth Pharaoh of Ptolemaic Egypt. The decline of the Ptolemaic dynasty began under the reign of Ptolemy IV.