In the aftermath of the death of Ptolemy Keraunos chaos was brought to the Greek mainland. In this period 279 BC-277 BC, Ptolemy Epigonos fled to the Illyrian Kingdom. With the help of their King Monunius, Ptolemy Epigonos tried unsuccessfully to recover Macedonia and again probably in 278 BC without success. He is mentioned as one of the claimants in the period of anarchy following the reign of Sosthenes. The chaos lasted until Antigonus II Gonatas defeated the Gauls in battle near Lysimachia, Thrace in 277 BC. After his victory, Antigonus II was recognised as Macedonian King and his power extended to southern Greece. After his failed attempted to regain the Macedonian Kingdom, Ptolemy eventually went to the Ptolemaic Kingdom to live with his relatives. Ptolemy II then was married to his only remaining half-paternal sister Arsinoe I by whom he had two sons: Ptolemy III Euergetes, Lysimachus of Egypt and a daughter Berenice. At an unknown date between after 279 BC-274/3 BC, Ptolemy's mother arrived in Egypt. Probably at the instigation of Arsinoe II, charges of conspiring to assassinate Ptolemy II were soon brought against Arsinoe I. Ptolemy II had convicted Arsinoe I of plotting against him. He ended his marriage to Arsinoe I and divorced her. Ptolemy II had exiled Arsinoe I to Coptos in southern Egypt. Ptolemy's mother married his maternal uncle Ptolemy II where she became through marriage an Egyptian Queen. Arsinoe II died at an unknown date between July 270 BC-260 BC. Ptolemy II at some point after his mother's death, had his children legally declared as the children of Arsinoe II and had the sons of Arsinoe II legally declared as the children of Ptolemy II. Ptolemy Epigonos disappears from the historical records from the time of his failed attempt to reclaim the Macedonian throne till the death of Arsinoe II. According to surviving portraits, inscriptions, coinage and papyri, Ptolemy was made co-regent of the Ptolemaic Kingdom by Ptolemy II. There may have been several reasons why Ptolemy II made Ptolemy his co-regent: to relieve him of some of his duties; to have the remaining living child of Arsinoe II to have as a help rather than a burden and support for the Chremonidean War which began at the beginning of the co-regency.