The poem outlines a theory of literary composition and criticism based on ancient Greek and Roman sources. Allusions to classical sources pervade the poem. The allusions set apart Horace’s poem from a conventional treatise. For example, Horace writes, “Homer has instructed us in what measure the achievements of kings, and chiefs, and direful war might be written,” an allusion to stories from the Iliad and Odyssey (Lines 73-98, Paragraph 1).

Although poets have the power of conjuring images and sounds from the imagination, they too have a responsibility to instill harmony in the subject matter, the precision of form, and the adherence to tradition. Here, the theme of The Necessity of Unity and Consistency appears through Greco-Roman references and allusions. The principles of organization, arrangement, and word choice fall under these thematic categories. In this respect, Horace endorses an adherence to a classical canon of literature that exemplifies unity and consistency. Yet Horace allows poets, whose innovation in language exceeds the capacities of their artistic predecessors, the right to amend and enhance tradition: “As leaves in the woods are changed with the fleeting years; the earliest fall off first: in this manner words perish with old age, and those lately invented flourish and thrive, like men in the time of youth” (Lines 44-72, Paragraph 1).