Romeo and Juliet contains several sonnets. A traditional form of poetry comprised of fourteen rhyming lines. They were typically about love. Shakespeare himself wrote sonnets, as many other poets did. They're inspired by Italian writers; more specifically, the Italian writer Petrarch. He established that they should be about pure, perfected spiritual love. His poems would compare love to religious pilgrimage, which Romeo and Juliet do when they first meet. Shakespeare uses the sonnets to demonstrate Romeo's growing maturity as a lover. And, to make love seem impossibly wonderful. As, Petrarch would often make extreme, unlikely comparisons. I hope this helps you! :-)