24 See the comprehensive analysis of O. Rossi, Letters from Far Away: Ancient Epistolary Travel Writing and the Case of Cicero's Correspondence (dissertation Yale, 2010), 34–122, also White, op. cit. (n. 1), 75–6. Perhaps many of our letter writers did provide dates for letters in the original autograph (cf. Cic., Att. 3.23.1); but such chronological material is highly vulnerable to removal in the process of editing and (particularly) transmission: see White, op. cit. (n. 1), 202 n. 52. Among documentary papyri surviving from Egypt, official or contractual letters are usually dated, but private letters often are not; see White, J. L., Light from Ancient Letters (1986), 5–8Google Scholar. But for the presence of ‘archon’ dates in the letters of Epicurus, see B. Inwood, ‘The importance of form in Seneca's philosophical letters’, in Morello and Morrison, op. cit. (n. 10), 133–48, at 143–4.