Cicero to C. Trebatius Testa in Gaul, written from Rome in the early days of February 53 BC. Vibius Pansa, returning from Caesar’s camp, has reported to Cicero that Trebatius has gone over to Epicureanism; Cicero, mock-scandalised, writes at once. The joke is a triple one: at the camp at Samarobriva (Caesar’s winter quarters in Belgic Gaul) for breeding philosophers fit only for seaside Tarentum; at Trebatius, who has apparently picked up his new doctrine from Pansa’s circle; and at the friend “Zeius,” whose name in the manuscripts is corrupt but who was evidently another Epicurean of Cicero’s acquaintance, sufficient to make Trebatius’s earlier orthodoxy already a little suspect.

The second paragraph is sustained legal-philosophical banter. Epicureanism, with its principle that pleasure is the measure of all things and that the wise man should not enter public life, is set against the formulae of the civil law in which Trebatius is a recognised expert: the action on a fiduciary trust, with its standard phrase ut inter bonos bene agier oportet; the action communi dividundo for partitioning common property; and the archaic oath per Iovem lapidem, sworn over a stone with imprecations on perjury — all of them, Cicero says, drained of force on Epicurean premises. The final swipe is at the wretched Latin town of Ulubrae, whose population (later the buzzing frogs of 7.18) will have no civic life left to them if Trebatius adopts the Epicurean lathe biosas. The Greek verb politeuesthai — “to take part in public life” — clinches the point. Cicero closes with a half-serious request for news.