Ptolemy II became co-regent with his father in about 290 BC, and sole ruler of Egypt in 283 BC (until 246). At that time he was married to ArsinoŽ I of Thrace. He repudiated her in 278, however, allegedly because she had participated in a conspiracy against him. Subsequently he married his sister ArsinoŽ II, which brought him her Aegean possessions and the nickname Philadelphus, the sister-loving. For Greeks and Macedonians, this marriage was a scandal. For the Egyptians, on the other hand, endogamous marriages were nothing unusual; in this way, the pharaohs had tried to keep power within the family since time immemorial.