A major theme of Horace’s poem is the requirement of unity and consistency in verse. Horace argues that all the best poets and dramatists of the Greek tradition, like Homer and Euripides, wrote their plots, characters, and settings in harmony with their formal techniques. The form will depend on the elements of the narrative. Yet precision in beautiful description lends nothing to a poem if the poet cannot properly begin or finish their work. The purpose of poetry is twofold: It must be beautiful and pleasing to its audience. Unity is not only integral to beauty but also favored by learned audiences. This theme corresponds to the writing process. Horace insists that poets must feel the emotions they wish to impart before writing those emotions into the plot and characters: “If you would have me weep you must first express the passion of grief yourself; then, Telephus or Peleus, your misfortunes hurt me” (Lines 99-124, Paragraph 1). Here, Horace speaks to the emotional relations between the author, the audience, and the work of art, including its characters, like Telephus and Peleus, two heroes of Greek mythology.

In the beginning of the poem, Horace constructs vivid examples of inconsistent writing to highlight the importance of unity.