Summary of Shelley's defence of poetry?

Percy Bysshe Shelleyâ??s â??A Defense of Poetryâ??, that argues on behalf of Romanticism poetry, was published posthumously in 1840. In it, he asserted â??Poets are the unacknowledged legislators of the world.â?? The defense was written in response to friend, Thomas Love Peacockâ??s article â??The Four Stages Of Poetryâ??.