Epic is a long poem in length about the doings of one or more characters from legend or history. These doings are something war-like that involves so many characters along with gods and spirits. The following are the conventions of the poetry:
A prayer or invocation comes at the beginning of the poem where the poet asks the god or muse to help him accomplish his great work. Milton uses this convention in his epic poem Paradise Lost as we note below:
… thou, O Spirit, that dost prefer
Before all temples the upright heart and pure
Instruct me, for though knowest: thou from the first
2. Homeric Simile:
Normally, an ordinary simile can describe a young man as ‘tall and dark and straight, like a young cypress tree’, on the contrary a Homeric simile expands the comparison to such an extent that it becomes a small poem within the poem. For example:
Like some young cypress, tall, and dark, and straight,
Which in a queen’s secluded garden throws
Its slight dark shadow on the moonlit turf
By midnight, to a bubbling fountain’s sound –
So slender Sohrab seem’d, so softly reared.
(Matthew Arnold’s Sohrab and Rustum (1822-88))
3. Athletic Contest or Games:
Homer used this convention and described how Achilles prearranged an athletic competition in the honor of his friend Patroclus. Then Virgil followed it and after this, it became an unavoidable convention without which epic was incomplete. Paradise Lost Book-2 describes the fallen angels arranging an athletic meeting.
4. Long and Adventurous Journey:
The hero makes such journey. For example, Aeneas’s journey to seek the spirits of Anchises. Milton describes Satan’s such journey via the space in his Paradise Lost.
5. in medias res:
According to this convention, the story has to begin in the middle of the action, in medias res, as Horace called it. For instance, The Aeneid begins with the arrival of Aeneas at Carthage. This is followed by the long story of the fall of Troy, his escape and his journey to the Carthaginian shore. Now most of the novels and movies make use of this convention.