In Greek mythology, Orchomenus (Ancient Greek: Ὀρχομενός) is one of the sons of Thyestes by a naiad whose flesh Atreus served to their father at the cannibal banquet of Mycenae. With his brothers Aglaus and Calaeus (Callileon) he is a tragic victim of the Atreid curse. He is not the Boeotian or Arcadian eponymous kings of the same name.
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I.The banquet of Atreus
After the feud between Atreus and Thyestes for the throne of Mycenae, Atreus murdered Thyestes's sons and cooked their flesh, serving it to Thyestes at a feast. Only after Thyestes had eaten did Atreus reveal the crime. Ancient catalogues name the victims Orchomenus, Aglaus, and Calaeus (Callileon in Apollodorus's Epitome).
The atrocity stands near the center of the Atreid curse: Thyestes's subsequent oracle, the birth of Aegisthus by Pelopia, and the murders that follow all answer this banquet. Orchomenus himself has almost no separate biography beyond his place among the slaughtered children.
II.Homonyms
The name Orchomenus belongs to several distinct figures: an Arcadian son of Lycaon and eponym of Arcadian Orchomenus; a Boeotian king, son of Minyas, eponym of Minyan Orchomenus; a son of Zeus and the Danaid Isonoe; a son of Athamas; and others. This atlas entry is only the Thyestes son named in the Atreid banquet tradition (Apollodorus Epitome 2.13).