the death of Patroklos is a function of his being the therapōn of Achilles: this word therapōn is a prehistoric Greek borrowing from the Anatolian languages… where it had meant ‘ritual substitute.’
Nagy’s central argument: Patroklos functions as the ritual substitute of Achilles, and his death is structurally determined by this prehistoric semantic role rather than by narrative accident.
, The Best of the Achaeans: Concepts of the Hero in Archaic Greek Poetry, 1979thesis