This allusion provides a good illustration of the workings of the Iliad’s performance context. Diomedes says only that Tydeus is able to “mastermind astounding deeds” with Athena’s help on this occasion, without any further detail needed for his internal audience, since Athena would know what happened. A traditional audience of the Iliad, however, would also readily know the events to which Diomedes refers, and this compressed reference would evoke the entire episode for them, whereas we have to try to reconstruct it as best we can. As we have seen, this episode is also related to Diomedes by Agamemnon at Iliad 4.382–398 and Athena at Iliad 5.800–808 as they both try to spur him on to live up to his father’s fighting prowess. As we saw above on 10.48, the phrase mermera erga refers to one man defeating many more, and Tydeus does this twice, in fact, when he is sent alone to Thebes as a messenger. In Iliad 4 and 5, we learn that Tydeus challenges the Thebans to athletic contests, and defeats them all easily, because Athena helps him (Iliad 4.389–390 ≈ 5.807–808). But in Iliad 4, Agamemnon continues the story by saying that the Thebans in retaliation send fifty men to ambush Tydeus (they go on a πυκινὸν λόχον, Iliad 4.391–393; see above at 10.5–9 for the implications of pukinos in an ambush context). Tydeus defeats them as well, slaying all of them except for Maion, whom he intentionally leaves alive in obedience to the portents of the gods (Iliad 4.396–398). The A scholia on Iliad 4.394 inform us that “some guess that Maion was a herald, and for that reason he alone was saved.” Nevertheless, Tydeus’ status as angelos does not protect him from being attacked. In his much later (and Latin) epic Thebaid, Statius portrays Maion as a seer, and Tydeus makes him a herald by default, giving him the message to take back to Thebes to prepare for war (Thebaid 2.682–703).
We see here that, in addition to mermera erga indicating one man defeating many, it can apply to either daytime fighting in open battle (as in the case of Hektor above [10.48] and at Iliad 11.502, in the case of Achilles at Iliad 21.217, and in Zeus’ phrase πολέμοιό τε μέρμερα ἔργα at Iliad 8.453) or nighttime/ambush fighting, as in this case and also below on 10.524. Here and on 10.48, these astounding deeds are associated with verbs like μήδομαι (10.52 as well as this line) and μητίομαι (10.48), so whether daytime battle or nighttime ambush, whether attacker or attacked, such success against greater numbers can be thought of as “devised” or “masterminded.” Also, in this case, the fact that one ambusher is left alive is a significant detail. In the poetics of ambush, there is narrative tension surrounding the possibility of not knowing what happens to those who go on a spying mission, an ambush, or another nighttime expedition unless they return successfully. Maion’s return, although apparently granted by the gods, is also necessary for Tydeus’ victory to be known.
This allusion indicates that ambush was a theme in the Theban epic tradition as well. Like Bellerophon (Iliad 6.187–190), Tydeus is successful in defeating the ambushers even though he is vastly outnumbered. Another night episode within this tradition that shares features with Iliad 10 is Tydeus’ arrival in Argos after his exile. The scholia to Iliad 4.376 from the Venetus A relate the story that both Tydeus and Polyneikes arrive at the house of Adrastos at night, each wearing an animal skin, like those of the heroes in Iliad 10. Tydeus wears a boar skin, and Polyneikes a lion skin. Adrastos had received an oracle that he should marry his daughters to a lion and a boar, and seeing these men on his doorstep he realizes that they should be his sons-in-law. As we have argued above, the wearing of animal skins puts the episode in a distinct register. The connection to the animals mentioned in the oracle plays off that register, by making the meaning of the skins symbolic in a more particular way. See also the commentary on Dolon’s wolf skin at 10.334.