Rhyme in Ode on a Grecian Urn

Text of the Poem 1
"express..."   (Text of the Poem)

Keats writes this poem in iambic pentameter and uses an alternating rhyme scheme in the first four lines of each stanza. The rhymes are not always perfect rhymes, and the best example of this is the slant rhyme in the fourth stanza. Although he uses rhyme throughout the piece, he does not use a strict rhyme scheme anywhere else, except in the first four lines of each stanza.