Longinus outlines five sources of sublimity in literature:
Greatness of thought (lofty cast of mind)
Strong emotion (vigorous treatment of passions)
Appropriate use of figures of speech and thought
Nobility of diction (majesty of the structure)
Dignified and elevated composition (wide range of thoughts)
Among these, Longinus considers the "greatness of thought" or "a lofty cast of mind" to be the most important condition. This concept emphasizes that a writer must possess a certain grandeur and elevated mindset to produce truly sublime work. This inner greatness influences all other aspects of writing, ensuring that the emotions, figures of speech, diction, and composition are all marked by sublimity.