Laomedon (lāŏm´Ĭdŏn), in Greek mythology, king of Troy. When Laomedon failed to pay Poseidon, Apollo, and King Aeacus for building the walls of Troy, Poseidon sent a sea monster to ravage the land. Total catastrophe could be averted only by the sacrifice of Laomedon's daughter, Hesione. Laomedon offered Hercules a pair of immortal horses if he would rescue his daughter. Hercules slew the sea monster and saved Hesione but Laomedon refused to give him the horses. In revenge, Hercules sacked Troy and killed Laomedon and all his sons except Priam, who became the new king of Troy.