Following the Battle of Corupedium, Lysimachus' widow, Arsinoe, flees to Cassandrea, a city in northern Greece, where she marries her half-brother Ptolemy Keraunos. This proves to be a serious misjudgement, as Ptolemy Keraunus promptly kills two of her sons, though the third is able to escape. Arsinoe flees again, this time to Alexandria in Egypt.
Seleucus takes over Thrace and then tries to seize Macedonia. However, he falls into a trap near Lysimachia, Thrace, set by Ptolemy Keraunos, one of the sons of Ptolemy I and Arsinoe II's half brother, who murders Seleucus and takes Macedonia for himself.