The heroic age of Greece, like the heroic age of western Europe, practised trial by combat. For a combat to be judicial (a) it must be single combat, (b) it must be of numinous import, as evidenced among the Greeks by a connexion with divination in the form of oracle or prophecy, and (c) there must be a dispute the issue of which is to depend on the result of the combat. Not all single combat is judicial, for such a combat may be fought simply for honour and not to decide a dispute, as when Hector and Ajax fight on a challenge of Hector's to the best of the Achaeans to decide which shall have the honour of killing the other and bearing his arms away in triumph (Iliad H 77–83).

The institution of judicial combat is illustrated by a golden passage in the Iliad in Book Γ describing the duel between Menelaus and Paris. The Achaeans and the Trojans agree, after a challenge by Paris, that Menelaus and Paris shall fight in single combat, the terms being that if Paris kills Menelaus he is to retain Helen and her possessions, while if Menelaus kills Paris, then the Trojans are to return Helen and her possessions and pay the Achaeans a proper recompense. After performing the due rites Agamemnon formally recites these terms and threatens to fight to the end if the Trojans should break their word. Hector and Odysseus mark out a space and settle by lot which of the two combatants is to throw his spear first, while the Trojan and Achaean spectators pray to Zeus for death to the man who is responsible for bringing all the trouble on them.