I. One of the most famous of the Grecian heroes at the siege of Troy, and after Achilles considered the bravest of all the Greeks. According to Homer, his father Ty-deus was one of the leaders in the expedition of the seven against Thebes, and was killed be-fore the walls of that city, while Diomedes was still a boy. Having arrived at the age of manhood, he joined the second expedition against Thebes, and avenged his father's death. With 80 ships he sailed in the great Grecian armament to the siege of Troy, where, besides many victories over heroes of less note, he put Hector and AEneas to flight, and wounded both Venus and Mars. He was also famed for his wisdom in council, and when Agamemnon proposed to abandon the siege, Diomedes declared that he with his friend Sthenelus would remain until Troy should fall. According to later legends, he carried off with Ulysses the palladium from Troy. Of his history after the fall of the city Homer gives no account, but later writers tell us that having returned to Argos and found his wife unfaithful, he abandoned his native country. Traditions differ with regard to his after life.

According to some accounts, he went to AEtolia, and afterward returned and gained possession of Argos. Another relates that, in attempting to return to Argos, he was driven by a storm upon the coast of Italy, where he was kindly received by King Daunus, whom he assisted in a war against a neighboring tribe, and whoso daughter Euippe he received in marriage. II. A king of the Bistones in Thrace, son of Mars and Cyrene, celebrated for his mares, which ho fed upon human flesh. To obtain possession of these mares was one of the twelve labors of Hercules. The hero slew Diomedes, whose body he gave to the mares, which became tame after eating their master's flesh.