In Homer’s Iliad, Rhesus was the Thracian king killed by Diomedes during a night raid.
Rhesus arrives to support Troy with a contingent of Thracian warriors. In the Iliad’s nighttime episode, Dolon tells Odysseus and Diomedes where the Thracians are sleeping and describes Rhesus’s distinctive horses and splendid equipment.
Diomedes enters the camp while the soldiers sleep. He kills Rhesus and several of his men, while Odysseus steals the famous horses. The raid takes place before Rhesus can fight in the main battles around Troy.
Later traditions expand Rhesus’s story, and he became the central figure of Euripides’ tragedy Rhesus. The Iliad’s account is comparatively brief, but it gives the Thracian king a memorable role in the war’s night fighting.