sentences:  The king had believed, correctly, that Cassander would not do the same to Sophia, but would instead keep her in her place so that his son could attain the crown by marrying her.With the secret revealed, Demetrius is now recognized as the rightful king, and Sophia is displaced from direct power.Arcadius's fiancée, Polidora, is suddenly superseded when the Queen decides to marry him — as Lisimachus is displaced at the same time.