Rhesus (Ῥῆσος, Rhēsos) is an Athenian tragedy that belongs to the transmitted plays of Euripides. Its authorship has been disputed since antiquity, and the issue has invested modern scholarship since the 17th century when the play's authenticity was challenged, first by Joseph Scaliger and subsequently by others, partly on aesthetic grounds and partly on account of peculiarities in the play's vocabulary, style and technique. The conventional attribution to Euripides remains controversial. Rhesus takes place during the Trojan War, on the night when Odysseus and Diomedes make their way covertly into the Trojan camp. The same event is narrated in book 10 of Homer's epic poem, the Iliad. In the middle of the night, Trojan guards on the lookout for suspicious enemy activity sight bright fires in the Greek camp. They promptly inform Hector, who almost issues a general call to arms before Aeneas persuades him this would be ill-advised. The best course, Aeneas argues, would be to send someone to spy on the Greek camp and see what the enemy is up to. Dolon volunteers to spy on the Greeks in exchange for Achilles's horses when the war is won. Hector accepts the offer and sends him out. Dolon leaves wearing the skin of a wolf, and planning on deceiving the Greeks by walking on all fours. Next, Rhesus, the king of neighboring Thrace, arrives to assist the Trojans soon after Dolon sets out. Hector berates him for coming so many years late, but accepts his arrival; Rhesus responds that he had intended on coming from the beginning, but had been sidetracked defending his own land from an attack by Scythians. Meanwhile, making their way to the Trojan encampment with the intention of killing Hector, Odysseus and Diomedes run into Dolon and kill him. When they reach their destination Athena guides them to Rhesus' sleeping quarters instead of Hector's, warning them that they are not destined to kill Hector. Diomedes kills Rhesus and others, and Odysseus takes his prized horses, before making their escape.