Shakespeare said about poetry,
“The truest poetry is the most feigning;
and lovers are given to poetry; and what they swear in poetry
may be said, as lovers, they do feign.”
Poetry and love could be interpreted many different ways. The stereotypical view that poetry is something that somebody writes to the lover perhaps derived from Shakespeare's sonnets.
One of my favorite poems about romantic love comes from Romeo and Juliet, it says,
"Love is a smoke raised with the fume of sighs,
Being purged, a fire in sparkling in lovers' eyes,
Being vexed, a sea nourished with lovers' tears,
What is it else? A madness most discreet
A choking gall and a preserving sweet."
-William Shakespeare
Romeo and Juliet, Act 1, Scene 1, Page 10
