Calchas is an Argive mantis, or seer, in Greek mythology. Calchas appears in the opening scenes of the Iliad and also has a long literary history after Homer.
Calchas presides at the sacrifice of Iphigeneia, the daughter of Agamemnon, as the divine price of the winds required to carry the fleet to Troy, in a peristyle fresco from Pompeii.
In Greek mythology, Agamemnon was a king of Mycenae who commanded the Achaeans during the Trojan War. He was the son of King Atreus and Queen Aerope, the brother of Menelaus, the husband of Clytemnest
Calchas
…Theoclymenus. It was Calchas who prophesied that in order to gain a favourable wind to deploy the Greek ships mustered in Aulis on their way to Troy Agamemnon would need to sacrifice his daughter, Iphigeneia, to appease Artemis, whom Agamemnon had offended. The episode was related at length in the lost Cypria…
Fifth century BC depiction of Agamemnon seated while holding his scepter.
Fourth century BC depiction of Chryses attempting to ransom his daughter Chryseis from Agamemnon.
The Sacrifice of Iphigenia by Charles de La Fosse
Achilles' surrender of Briseis to Agamemnon, from the House of the Tragic Poet in Pompeii, fresco, 1st century AD, now in the Naples National Archaeological Museum