Calchas

Calchas, son of Thestor, was an Argive seer, with a gift for interpreting the flight of birds that he received of Apollo. He also interprets the entrails of the enemy during the tide of battle. It was Calchas who prophesied that in order to gain a favorable wind to deploy the Greek ships mustered in Aulis on their way to Troy, Agamemnon would need to sacrifice his daughter, Iphigenia, to appease Artemis, whom Agamemnon had offended; the episode was related at length in the lost Cypria, of the Epic Cycle. He also states that Troy will be sacked on the ninth year of the war.