Hesione ­ daughter of Laomedon, King of Troy, and sister of Priam.  She was to be sacrificed to a sea monster as a result of her father not paying Apollo and Poseidon after they built the walls of Troy for him, and Heracles rescued her on the understanding that Laomedon would give him divine horses. Laomedon refused, and Heracles killed him and all his sons save Priam. Laomedon was buried near the Scaean Gate, and, according to legend, as long as his grave remained undisturbed the walls of Troy would remain impregnable.