What Longinius does in this early work of ancient criticism is to define the sublime as an ideal that all authors should aspire to reach through their skill. What he outlines are the five sources of the sublime that need to be achieved in order for sublime literature to be produced. The first two relate to genius in the author, and Longinius states that grandeur of thought and the vivid portrayal of the passions are necessary pre-requisites in the author if sublime literature is to be produced:
First and most important is the power of forming great conceptions... Secondly, there is vehement and inspired passion. These two components of the sublime are for the most part innate.
The last three, Longinius argues, are different from the first two in that they relate to art rather than innate abilities that the author must have. Any work that is sublime must use appropriate imagery, "noble diction" and lastly be "dignified and elevated" in terms of its composition. These are the five tests of sublime literature that Longinius introduces in this work of classical criticism.