Laudator Temporis Acti

Gian Biagio Conte, The Poetry of Pathos: Studies in Virgilian Epic (Oxford: Oxford University Press, 2007), pp. 193-194:

In the epic duel, when two heroes meet and one addresses the other, the rule holds good that whoever emerges victorious in the encounter is either the only one to speak, or the last speaker. To put it in another way, the loser (or the one destined to lose) does not speak last in this kind of scene. In surviving Graeco-Roman epic, this rule is followed in some thirty cases (they mostly belong to the two Homeric poems and the Aeneid) and breached in only one case known to me, in the representation of the death of Mezentius. After the exchange of challenges and provocations (Mezentius shouts, summoning Aeneas to the encounter; Aeneas hastens and utters a few words, which Mezentius proudly rejects), Mezentius is laid low and Aeneas taunts him, according to the code for the victor, before administering the fatal blow. But, against the rule, the text allows Mezentius to speak again: he himself claims not to fear death, and even confirms that killing in battle is just and proper.