While the classical history says that Agathokles was innocent of conspiring against his father, Lysimachos, I’m not entirely sure of that. He had two cities named for him – with Adramytion the other. It’s also far too commonly told where the conniving wife sinks her husband or husband’s sons from a previous marriage in favor for another.
Then again, it could be true. It certainly was in Arsinoe II‘s advantage to do away with Agathokles.