One of the most highly regarded and popular poems in Shakespeare's sonnet cycle is "Sonnet 130." In this unusual poem Shakespeare argues against the convention of using similes of nature to describe the beauty of the lady. As mentioned on prior occasions, a convention of love poetry for many, many years was the use of similes. Writers creating love poems for their ladies would often compare their beauty to the beauty found in nature. Her eyes are as bright as the sun. Her lips are as red as roses. Even by the 1590's such similes had become cliches. They were just used too often. So, Shakespeare wrote "Sonnet 130" as a reaction against the use of similes in this fashion. Actually, Shakespeare accomplishes two purposes in this poem: (1) He mocks or ridicules the convention of using similes, and (2) he praises the beauty of the Dark Lady.
The structure of this poem relies on the division between the three quatrains and the couplet. In the quatrains (lines 1-12) Shakespeare contrasts the beauty of nature to the Dark Lady (the first purpose), but in the couplet he praises her beauty (the second purpose).
In the first quatrain Shakespeare begins by negating or by invalidating the most common of similes -- the comparison of a lady's eyes to the sun. Shakespeare is, in essence, saying let us be practical. Let us be real. No one's eyes are as bright as the sun. Such a comparison is an exaggeration. Such an