(Ptwlmys) King of Egypt, son of Ptolemy II and Arsinoe I, known as Evergetes ("the benefactor"), or also as Tryphon. Ptolemy III was able to access the throne while his rights were questioned by Arsinoe II, the new thought of his father. Very soon, in 246 BC, began to reign with the name neswt bity of Iua-in-netjerui-senui in-Ra Setep Sekhem - ankh - en - Imen. He/She married Berenice II, sister of Magas of Cyrene (son of Ptolemy I), which meant the recovery of that region to Egypt. On the other hand, his sister, also name Berenice, wife of Antiochus II, requested assistance to deal with the intrigues that had caused the death of her husband. Until Ptolemy III came to his aid, the own Berenice and her son had been killed. As revenge, Ptolemy III sacked Antioch, beginning thus the third Syrian war (246-241 BC), in which he/she faced Laodice, the first wife of Antíoco II, and his son. Ptolemy III carried their weapons even against own Babylon, of which extracted rich spoils which allowed him to recover the statues of Egyptian gods carried there time ago by Darius II and Cambyses II, known by the registration of the town of Adulis, on the Red Sea. The text lists all his conquests in Babylon, Susania, Asia minor, Thrace, and Ethiopia. A series of disturbances arising in Egypt was forced to interrupt their campaigns and return. Signed peace in 241 BC, Ptolemy III helped the achaean League and Cleomenes of Sparta against Macedonian rule in Hellenic lands.
Ptolemy III was very educated man; He/She was a friend of Eratosthenes and came to receive teachings from Apollonius of Rhodes. To reorganize the Administration, he/she tried to impose a new calendar (Decree of the year 238 BC CANopen), but did not succeed. Also had to devalue the coinage of currency in the absence of silver, which started a period of inflation and economic decline. Is Ptolemy III the beginning of the construction of the Temple of Horus in Edfu, which would be opened later, in the time of Ptolemy VIII. At his death, possibly poisoned, his son Ptolemy IVsucceeded him.