On this, the younger Ptolemy, the brother of Philometor, who was with his sister Cleopatra in Alexandria, and was about fifteen years old, declared himself king, and sent ambassadors to Rome to ask for help against Antiochus; and taking the name of the most popular of his forefathers, he called himself Euergetes.  He is, however, better known in history as Ptolemy Physcon, or bloated, a nickname which was afterwards given to him when he had grown fat and unwieldy from the diseases of luxury.

Comanus and Cineas were the chief advisers of the young Euergetes; and in their alarm they proposed to send the foreign ambassadors to meet the invader on his march from Memphis, and to plead for peace.  This task the ambassadors kindly undertook.  There were then in Alexandria two embassies from the Achaians, one to renew the treaty of peace, and one to settle the terms of the coming wrestling match.  There were there three embassies from Athens, one with gifts from the city, one about the Panathenaic games, and one about the celebration of the mysteries.  There was also an embassy from Miletus, and one from Clazomenae.  On the day of their arrival at Memphis, Antiochus feasted these numerous ambassadors in grand state, and on the next day gave them an audience.  But their arguments for peace carried no weight with him; and he denied that his father, Antiochus the Great, had ever given Coele-Syria as a dower with his daughter Cleopatra to Epiphanes.  To gain time he promised the ambassadors that he would give them an answer as soon as his own ambassadors returned from Alexandria; and in the meanwhile he carried his army down the Nile to Naucratis, and thence marched to the capital to begin the siege.

Antiochus, however, was defeated in his first assault upon Alexandria, and finding that he should not soon be able to bring the siege to an end, he sent off an embassy to Rome with a hundred and fifty talents of gold, fifty as a present to the senate, and the rest to be divided among the states of Greece, whose help he might need.  At the same time, also, an embassy from the Rhodians arrived in the port of Alexandria, to attempt to restore peace to the country of their old allies.  Antiochus received the Rhodian ambassadors in his tent, but would not listen to the long speech with which they threatened him, and shortly told them that he came as the friend of his elder nephew, the young Philometor, and if the Alexandrians wished for peace they should open the gates to their rightful king.  Antiochus was, however, defeated in all his assaults on the city, and he at last withdrew his army and returned to Syria.  He left Euergetes, King of the Greeks, at Alexandria, and Philometor at Memphis, King of the rest of Egypt.  But he kept Pelusium, where he placed a strong garrison that he might be able easily to re-enter Egypt whenever he chose.