War soon broke out again. Ptolemy had been expanding his power into the Aegean and to Cyprus, while Seleucus went on a tour of the east to consolidate his control of the vast eastern territories of Alexander's empire. Antigonus resumed the war, sending his son Demetrius to regain control of Greece. In 307 he took Athens, expelling Demetrius of Phaleron, Cassander's governor, and proclaiming the city free again. Demetrius now turned his attention to Ptolemy, invading Cyprus and defeating Ptolemy's fleet at the Battle of Salamis. In the aftermath of this victory, Antigonus and Demetrius both assumed the crown, and they were shortly followed by Ptolemy, Seleucus, Lysimachus, and eventually Cassander.