Talthybius (Greek: Ταλθύβιος) was herald and friend to Agamemnon in the Trojan War. He was the one who took Briseis from the tent of Achilles. Preceding the duel of Menelaus and Paris, Agamemnon charges him to fetch a sheep for sacrifice. He died at Aegium in Achaia.
Talthybius appears in Euripides’ Hecuba and The Trojan Women. In addition, he has a small role in The Iliad. In The Iliad, Agamemnon orders Talthybius to fetch the medic Machaon after Menelaus was wounded with an arrow shot by Pandarus. In Hecuba and The Trojan Women, Talthybius seems to always be the bearer of bad news. In The Trojan Women, he tells Hecuba that all of the women are being divided up and given to different Greek Heroes as slaves. He says that Cassandra will be given to Agamemnon and that Hecuba herself will be given to Odysseus. Furthermore, Talthybius is the one who tells Andromache of the Greeks’ plan to kill Astyanax, her son by Hector. The plan is to throw Astyanax (who is only a small child) from the towers of Troy because it would not be wise to let the son of a Trojan hero reach adulthood. In Hecuba, Talthybius brings an order from Agamemnon to Hecuba, telling her to bury her daughter, Polyxena, who was sacrificed to Achilles.
3564 Talthybius is a Jupiter Trojan asteroid that orbits in the L4 Lagrangian point of the Sun-Jupiter system, in the "Greek Camp" of Trojan asteroids. It was named after the Greek hero Talthybius, who was a herald during the Trojan War. It was discovered by Edward L. G. Bowell on October 15, 1985 in Flagstaff, Arizona at the Anderson Mesa station of the Lowell Observatory.
Photometric observations of this asteroid during 1994 were used to build a light curve showing a rotation period of 40.59 ± 0.13 hours with a brightness variation of 0.38 ± 0.01 magnitude.