Features of Epic Poetry (Aristotle)
Epic poetry agrees with Tragedy in so far as it is an imitation in verse of characters of a higher type. They differ, in that Epic poetry admits but one kind of metre, and is narrative in form (Aristotle 15)
Heroic metre is dactylic hexameter. That is six feet to the line, the first five feet being either a dactyl (- uu) or a spondee ( – -). The last always a spondee (- -) or a variation.
Aristotle, Poetics and Rhetoric. Barnes and Noble Classics: New York. 2005.