Sublime (ὕψος‎‎ Sublimitas), that quality of genius in great literary works which irresistibly delights, inspires, and overwhelms the reader.

Although ancient rhetoric, in its theory of the three genera dicendi (e.g. Cicero, Orat. 21. 69; Quintilian, Inst. 12. 10. 58), distinguished a grandiloquent style, for arousing the listeners' passions (ἁδρόν‎‎, grande, vehemens, sublime), from a dry one, for demonstrating by arguments (ἰσχνόν‎‎, subtile, tenue, gracile), and a moderate or ornate one, for providing pleasure (γλαφυρόν‎‎, medium, mediocre, floridum), the isolation and glorification of the sublime as a central aesthetic category is largely the achievement of the anonymous author of the treatise Περὶ ὕψους‎‎, ‘On the sublime’ (1st cent. ce), long attributed to Cassius Longinus (see 'longinus'). Applying Platonic views on poetic inspiration to the needs of the rhetorical schools, ps.-Longinus emphasizes the imaginative power of the canonical poets and prose authors of earlier periods (Homer, Demosthenes (2), but also Genesis and Cicero), which enthrals, enhances, yet also annihilates the reader. The quality of the sublime usually (but cf. 35. 3–4) attaches to works of literature rather than to natural phenomena and (much like Matthew Arnold's ‘touchstones’) less to whole works than to individual passages. It results from a superhuman natural capacity, not just study; yet specifiable rules and techniques produced it once and can produce it even today—or, if violated, can obstruct it, resulting in such faults as pomposity or frigidity. Hence, though the present age is mediocre in comparison with the greatness of the past, the sublime provides a channel whereby the ancients' enthousiasmos can lift us above our quotidian banalities and put us in touch with finer minds and, above all, with more unobstructed emotions.

‘Longinus'’ treatise, less impressive for systematic rigour than for its own enthusiasm and its lively appreciation of the classical authors, seems to have had no impact upon ancient rhetorical theory and reached the Middle Ages only in a single, incomplete manuscript; even after its rediscovery in the Renaissance it was only in the late 17th cent. that it entered French Neoclassical literary discussion, largely via Boileau's paraphrase. Thereafter the sublime became a central category of 18th- and 19th-cent. literary criticism and philosophy (Burke, Kant, Hegel) and of Romantic poetry (Wordsworth, Hölderlin, Leopardi). Whether nature could be sublime and which arts, authors, works, etc. were most sublime were hotly debated questions. By the mid-19th cent. the concept's popularity as an object for serious aesthetic speculation had crested, though the word has remained alive in ordinary vocabulary to express unreserved, unspecific approval—thereby returning to something like ps.-Longinus' own usage.