The following document is a translation of Aristotle's Poetics written in 350 B.C. The Poetics contains our first definitions of common literary terms such as comedy, tragedy, and epic poetry. It is a useful exercise for us to use this definition as a guide to our modern conceptions of these terms.
In the Poetics, Aristotle attempts to solidify definitions for both poetry and drama, trying to answer the following questions:
What is the difference between Epic Poetry (highest form of poetry) and common poetry?
What is the difference between Tragedy (highest form of drama) and Comedy (low drama)?
Aristotle has very clear opinions on the differences between what he deems to be "common" versus what he thinks is a "higher form and Purpose" in both poetry and drama.
For our look at Tragedy, read sections VII through XVIII, and take notes/annotate the text!
Citation:
Aristotle. "Poetics Trans. S. H. Butler." Internet Classics Archive. MIT, 2009. Web. 3 Sept. 2015.