Longinus was a Greek rhetorician and philosopher in the 3rd century AD known for his literary criticism. He taught rhetoric in Athens and later advised Queen Zenobia of Palmyra before being executed as a traitor by the Romans. Longinus made important contributions as one of the first comparative critics, focusing on individual elements of texts and defining what makes a work a literary classic. His work "On the Sublime" analyzed what creates grandeur in literature and argued that great works not only please or instruct but also move and elevate readers. Longinus believed that a work becomes excellent when it has the power to sublime the reader through qualities like strength, vehemence or inspiration.