Ptolemy Keraunos
Arsinoe II's marriage to her half-brother was not happy. Through his marriage to Arsinoe II, Ptolemy Keraunos' political position was strengthened. As Ptolemy Keraunos was becoming too powerful, Arsinoe II conspired with her sons against him while he was away on a campaign. Ptolemy Keraunos quickly retaliated by capturing Cassandreia and killing Lysimachus and his brother Philip. Arsinoe II and Lysimachus' other brother Ptolemy were able to escape. Later on his brother Ptolemy and his mother fled to Egypt, where his mother married his other maternal uncle Ptolemy II Philadelphus.