One of the main characters of the Illiad, Diomedes is the son of Tydeus, one of the Seven Against Thebes, and the king of Argos. He is the youngest of the kings to participate in the war, yet he is one of the wisest. He is also the most valiant of the warriors, displaying courage when fighting in the front ranks, respect for his commander, king Agamemnon and the gods, and humility to remain within mortal limits, and the second strongest of the Greeks in the war, behind Achilles, but above even the mighty Ajax.
Just like his father, Diomedes was the champion of Athena. However, he was closer to the goddess than any other hero, or even than other gods. She personally helped him perform his greatest feat: wounding two Olympians in the same day. Diomedes also nearly killed Aeneas on the same day, which would cause Rome to never be founded, and successfully stole his horses, which descended from Zeus’ immortal horses, and were only second to Achilles’. Diomedes could also have been the one to kill Hector, if it wasn’t for Zeus’ intervention.
Diomedes was also very cunning. He knew that accepting the peace offered by Iadeus would be foolish, since they were winning, tricked Glaucus into giving him his golden armor, and helped Odysseus in many of his plots. Diomedes was also one of the warriors within the Trojan Horse. It was also Diomedes the one who stole the Palladium, the statue of Athena that assured that Troy would not fall as long as it remained within the city.
In the funeral games of Patroclus, Diomedes managed to win all the events in which he participated, even while wounded. He was the first to draw blood from Ajax in their battle, which had to be stopped because the Achaeans feared that another blow from Diomedes could kill Ajax.
After the Trojan War was over, Aphrodite took a small revenge against Diomedes, by helping his wife, who stayed in Argos, to gain many lovers. With their help, she kept Diomedes from entering the city that was rightfully his. Diomedes then went to Italy, where he helped King Daunus win a war, and for this was rewarded with land a marriage to the princess. Diomedes founded a total of ten cities in Italy, one of which was Aphrodisia (or Venusia), as a peace offering to the goddess of love. During the War between Aeneas and Turnus, Diomedes refused to help Turnus, saying that he had killed enough Trojans in his life, and that his purpose in Italy was to live in peace. He dedicated many temples in his kingdom to the goddess that helped him so much, Athena.
Little is known of how Diomedes died, but according to legend, albatrosses gathered around and sang a song when upon his death. Other legend says that his soldiers were turned into albatrosses by Venus (Aphrodite) in order to guard his tomb. However, many legends state that he did not face a mortal death, and instead was turned into an immortal and a lesser god by Athena.