Rhesus was a king of Thrace in Greek mythology, who sided with the Trojans during the Trojan War. He was the son of Eioneus, although later sources said that he was the child of the river god Strymon and one of the Muses. Right after the Greeks attacked Troy, his country was attacked by Scythia, so he was unable to join the Trojans early in the war. He was killed out of battle, while in his tent, and his horses were stolen by Diomedes and Odysseus. Upon seeing her son dead, his mother lay blame on all responsible parties, Diomedes, Odysseus, and the goddess Athena, and foresaw that Rhesus would be resurrected and become immortal.
See Also: Trojan War, Muses, Diomedes, Odysseus, Athena