The first half of Aiskhylos' "Agamemnon" presents three crimes of the House of Atreus: the sacrifice of Iphigeneia (184-247), the wasting of young Argive lives at Ilion (355-487) and the treading of the materials as the victorious king reenters his palace (810-974). We argue that the sequential presentation of the crimes of the House, which are connected thematically, stylistically, and causally, radically redefines the nature of transgression within contemporary models of the polis community. Crime as defined in relationship to oikos alone is displaced by crime as defined in relationship to both oikos and the broader polis community; transgression moves from an aristocratic (oikos alone) to an isonomic (oikos within polis) context. This redefinition culminates in the "Carpet-Scene." We reread Agamemnon's nostos as a contest of epinikia. The king represents himself as victorious idiôtês, and Klutaimestra strives to figure him as returning tyrant. She succeeds in the stichomythia, where Agamemnon fails to recognize the crucial distinction between φθόνος and ζῆλος. Aristotle differentiates the terms at Rhet. 1387-88, where φθόνος is envy toward a social superior and ζῆλος the emotion one experiences in rivalry between equals; we document the development of the terms from the archaic period onwards, demonstrate that Aristotle's distinction is valid for the late archaic and classical periods, and suggest that it arose in an attempt to outline relationships of appropriate and inappropriate competition among fellow-citizens. Agamemnon's failure to recognize this important distinction betrays his misunderstanding of the dynamics of, and his agreement to walk on the materials is an offense against, isonomic community. The rearticulation of the nature of transgression completed by this crime of Agamemnon against the polis does fundamental ideological work for the rest of the Oresteia, offering an aetiology of the claims of the polis against the aristocratic oikos.