A lofty, ennobling seriousness as the main characteristic of certain poetry, as identified in the treatise On the Sublime, attributed to the 3rd-century Greek rhetorician Cassius Longinus. The concept took hold in the 18th century among English philosophers, critics, and poets who associated it with overwhelming sensation. In A Philosophical Inquiry into the Origin of our Ideas of the Sublime and the Beautiful (1757), Edmund Burke identified the sublime as the experience of the infinite, which is terrifying and thrilling because it threatens to overpower the perceived importance of human enterprise in the universe. Aesthetes and writers of the era saw the natural world and its wild, mysterious expanses as a gateway to the experience of the sublime. Romantic poets such as Percy Bysshe Shelley and William Wordsworth were influenced by this notion.