When I think of sonnets, these are the first lines that pop into my head. Shakespeare's couplet illustrates the nature of sonnets- love poems that attempt to define love, woo, or mourn unrequited love.

I think this poem very powerfully uses the form of a sonnet. The usual remembrance or celebration of someone you love is replaced with an elegy to someone lost. The themes of love still come through and the poem is very poignant.

Shelley's language here and this sonnet overall differs from the traditional sonnet. It serves as an example of the multiple directions the form can be taken in. Shelley's invocation of blood and other violent imagery is much different from themes of unrequited love.