Cicero to Atticus, written from the Cuman villa on the sixth day before the Nones of May 49 BC (the manuscript dateline: Scr.\ in Cumano vi Non.\ Mai.\ a.\ 705 (49)). The longest letter in the Cuman stretch, and the most fully argued. Both Tullia and Atticus, in their last letters, have urged Cicero to wait on the outcome of the Spanish campaign before crossing to Pompey; the body of this letter is a careful, ordered case against waiting — a consilium that runs through the three possible outcomes in Spain, the question whether Spain even decides the larger war, the risk-calculus on both sides, and a final auguria drawn not from the College of Augurs and Attus Navius but from Plato’s analysis of tyranny. Cicero opens by signalling that the channel is now compromised — “it was time we put an end to writing between us” on dangerous topics — and only Tullia’s repeated entreaty has prompted him to break that silence.

The political diagnosis is the bluntest yet: if Caesar wins he sees “slaughter, an attack on private wealth, the recall of exiles, the cancelling of debts, honours for the most shameful men, and a kingship not merely intolerable to a Roman — intolerable to any Persian.” He calls Pompey’s strategy “Themistoclean” — a maritime war fought from a fleet, with the Spains not the centre of gravity — and frames his own deliberative choice against that scale: even if defeated, he will have chosen rightly. The Themistocles excursus in section 7 quotes Thucydides twice in the original Greek and is the most fully realised classical exemplum in the Cuman letters; section 8 is missing from the transmitted text. The letter ends warmly with thanks to Atticus for his care of Tullia (whose [Greek: storg\=e] and [Greek: synt\=exis] Cicero singles out), and with the announcement that Antony is due at Misenum that very day, the sixth before the Nones, having sent ahead a “tiresome letter” — the text of which the editors print as 10.8B, attached at the foot of this letter.