What is another word for "epistle"?

Roget's Thesaurus (1911) lists these synonyms for "epistle": billet, billet-doux, bulletin, card, chit, chitty, circular, correspond, correspondence, despatch, dispatch, epistolary, favor, keep, letter, messenger, missive, note, picture, post, postal, rescript, rescription, send, these, with, write.