Most of the literary theorists and critics of classical antiquity who are still studied today – Plato, Aristotle, ‘Longinus’, and a few others – are Greeks. The Romans, who by reputation came late to literature and lacked a theoretical cast of mind, are not generally accorded a prominent place in the development of this discourse. Indeed, few surviving Roman texts address as their main topic the business of literary criticism, at least as that phrase is understood today. Nevertheless, the critical discussion of literature was a popular social activity among the Roman elite and an obligation of the intelligentsia. Horace's Ars Poetica is the closest thing we have to a Roman treatise on literary theory. The only actual treatises on poetics after Aristotle that might be relevant to Roman literature have been found among the essays of the Greek philosopher and poet Philodemus of Gadara.
The fundamental effect of metre on language is to organise and regulate it; and language so structured automatically rises in status, gaining a heightened, even ritualistic character purely by virtue of the artificial patterns it is obliged to obey. What precisely is ‘measured’ by ‘metre’ varies. It may be the number of syllables, or the number of accentual stresses; it may be a combination of the two. Accentual stress had a role to play in Roman poetry, and there was also an element of syllable counting, seemingly inherited from the syllabic metres of the Indo-Europeans, the ancient common source of Greek, Roman, Indian, and other metrical systems. No other Roman poetry had quite so combative a relationship with its own metre as satire, but it could still be argued that Rome was never entirely at ease with its Greek metres. Metre is absolutely central to Horace's characterisation of Pindar and of himself.