A god answers plainly and means something else entirely, and armies die in the gap between his words and their sense. This shape reaches our shelf through Apollodorus's Library (a Greek mythography, 1st–2nd century CE compilation), in the long story of the Heraclids' struggle to return to the Peloponnese. Hyllus goes to Delphi to ask how the descendants of Hercules should come home, and the god tells him to "await the third crop" before returning. Hyllus takes the plain reading — three harvests — waits out the years, invades, and is slain. The oracle was true; his hearing was false.

The mistake is hereditary. When a later generation inquires again and receives "the same answer as before", Temenus reproaches the god, only to be told that they "did not understand the" oracles: by "the third crop" he had meant "not a crop of the earth, but a crop of a generation", the third generation, not the third year — and that "by the narrows he meant the broad-bellied" sea at the mouth of the Gulf, not the Isthmus of Corinth where they had thrown themselves against the enemy and lost. Every literal reading had been a trap the words themselves laid. After yet another disaster the god commands them to "take for his / guide the Three-eyed One", and they puzzle at it until they chance upon Oxylus "sitting on a one-eyed horse" — man and mount together making three eyes — and only then, "guessing the purport of the oracle", do they find their way in and win.

Thompson gives this the address of the ambiguous oracle, and Apollodorus's telling is its patient anatomy: not a lying god but a punning one, whose truth is exact and whose meaning is armored in riddle. The Heraclids do not fail for want of piety; they fail for want of interpretation, learning across three generations that to consult the divine is to be handed a puzzle, not an answer. When a true word can be understood two ways and only one of them spares you, whose fault is the blood — the god's, for speaking in riddles, or the hearer's, for choosing the easy sense?