For the Numonii, I think the winner is not the unfortunate cavalry officer killed after Teutoburg, nor the ancestor who supposedly stormed a vallum. It is the first Gaius Numonius Vala, Horace's correspondent in Epistles I.15. The reason is simple:  the entire surviving relationship consists of one man asking another for information.  That is already conversational philosophy. Horace writes to Vala because he wants to know:  what the climate is like, what the water is like, what the inhabitants are like, whether the place is worth spending the winter in.  The letter is a study in testimony. Horace cannot inspect Velia himself. He must rely on Vala's report. The whole exchange concerns the Gricean question:  When is someone's answer good evidence?   Grice et Numonius Vala G.: Qualis est hiems apud Veliam? ("What is the winter like at Velia?") Vala: Mitis. ("Mild.") G.: Et aqua? ("And the water?") Vala: Bona. ("Good.") G.: Et incolae? ("And the inhabitants?") Vala: Ferendi. ("Tolerable.") +> that they are not especially delightful.  G.: Cur non dicis eos bonos esse? ("Why do you not say they are good?") Vala: Quia quaesivisti; non quia laudandi sunt. ("Because you asked; not because they deserve praise.") +> that Vala is attempting to be informative rather than complimentary.  Grice/Speranza analysis This is wonderfully Horatian because Vala is functioning as what Grice would call a reliable informant. The point is not that he produces implicatures by saying too little. Rather, the point is that Horace's entire enquiry presupposes the Cooperative Principle. When Horace asks:  Qualis est regio?  he assumes that Vala will answer:  truthfully, relevantly, sufficiently, without ornamental patriotic nonsense.  In short, Horace relies upon all four Gricean maxims before Grice has existed.  My second choice would actually be the younger Gaius Numonius Vala, Varus' legate who escaped the infantry during the Teutoburg disaster and attempted to reach the Rhine with the cavalry before being overtaken and killed. That produces a fascinating vignette about military signalling, retreat, and whether one may infer "the battle is lost" from a commander's behaviour. But the Horatian Vala is better. Why? Because he gives Speranza something he always likes:  conversation before philosophy.  No tribunals, no imperial intrigue, no forged letters, no apotheosis. Just one Roman asking another:  "Should I spend the winter there?"  And trusting that the answer means exactly what it appears to mean. That trust, Speranza would say, is the quiet presupposition of every later theory of conversation. A dry closing formula might be:  Novius gave Rome a shadow from which to infer the hour. Numerius Atticus gave Rome a vision from which to infer a god. Numonius Vala gave Horace a report from which to infer whether the weather was worth enduring. Grice, being English, may ultimately have found the weather the most convincing topic of the three.