A young man arrives in a city where his father is king, and the father does not know him. The son carries a token; the recognition, when it comes, arrives at the last possible instant, a cup already lifted to poison him. This is the quest that ends not in a monster's death but in a face turning to say, at last, you are mine.

The witness is Apollodorus's Library (a Greek mythography compiled in the 1st–second century CE), which tells it of Theseus. Having cleared the road of its bandits, “Theseus came to Athens,” where Medea, then wedded to his father, “plotted against him” and persuaded the king to treat the stranger as a threat. So “Aegeus, not knowing his” own son, sends him against the Marathonian bull; when Theseus survives that, the king offers him a cup of poison Medea has supplied. The turn hangs on a blade: just as the draught is about to be drunk, “he gave his father the sword,” and “on recognizing it” “Aegeus dashed the cup from his hands.” The token does the work no words could—“Theseus was thus made known to his father”—and Medea is driven out. The mythographer notes the same claim from the other side elsewhere: “when Theseus appeared from Troezen, claiming” his place, the sons of Pallas learn who has come home.

Only this Greek witness truly stages the shape on our shelf. The other served rows drift off the motif—a Sanskrit episode of a low-born archer questioned in the woods about whose son he is, and a Florentine vision of an emperor reciting Rome's wars—near the words, but not the deed. Thompson's wider authorities, from an Irish tale-list to Hawaiian and Tongan tradition, wait unread.

The recognition token cuts both ways: it saves the son, and it indicts the father for nearly killing his own blood. When a myth makes a father almost murder the child he cannot recognize, what does it fear most—that fathers do not know their sons, or that sons must prove themselves before a father will?