Ptolemy III Euergetes was the third pharaoh of the Ptolemaic dynasty in Egypt from 246 to 222 BC. The Ptolemaic Kingdom reached economic and political zenith during his reign, initiated by his father Ptolemy II Philadelphus.
Ptolemy III was the eldest son of Ptolemy II and Arsinoe I. When Ptolemy III was young, his mother was disgraced and he was removed from the succession. He was restored as heir to the throne in the late 250s BC and succeeded his father as king without issue in 246 BC. On his succession, Ptolemy III married Berenice II, reigning queen of Cyrenaica, thereby bringing her territory into the Ptolemaic realm. In the Third Syrian War, Ptolemy III invaded the Seleucid empire and won a near total victory, but was forced to abandon the campaign as a result of an uprising in Egypt. In the aftermath of this rebellion, Ptolemy forged a closer bond with the Egyptian priestly elite, which was codified in the Canopus decree of 238 BC and set a trend for Ptolemaic power in Egypt for the rest of the dynasty.