Percy Shelly is an English poet during the Romanticism period. During the Romanticism, the poets were resisting traditional expectations and inventing new poetic forms. And the dominant literary form was the lyric poem. Also, as nature becomes more and more vulnerable and valued, Romanticism is associated with nature. In addition, Poet is seen as a new model of expressive freedom, which is liberated from the constraints of reason and authority. It is not only a very foundation for a new kind of society, but also a foundation for human experience, Thus, Romanticism is associated with nationalism as well. It is defined as a rejection of neoclassical styles and a rejection of reason as the organizing principle for art and society.

If we want to talk about Percy Shelly and his poems, we have to take the history background into account. Shelly experienced the era when the British government had imposed heavy taxes to pay for the nation’s protracted wars with France, with the poor suffering especially from high taxes. For example, Shelly describes large-scale historical events, and expresses his resistance and rebellion towards the authority in his poem, England in 1819, like he said, “Rulers who neither see nor feel nor know” and “Burst, to illumine our tempestuous day”. Shelly believes that only poetic images can be like the “redemption” to reanimate the literature. Such renewal of words could become a means of upending social inequities and tyrannical authorities.

In Shelly’s a Defense of Poetry, he first relates poetry to the remarks in its elements and principles, such as nature, to tell us what is called poetry. Like he said, “Poets are not only subject to these experiences as spirits of the most refined organization, but they can color all that they combine with the evanescent hues of this ethereal world;” That is, poetry makes our words, feelings, minds, and imaginations, all immortal. He then states an application of the principles to the cultivation of poetry by relating the nationalism background. The poets use poetry as an accumulation of the power if communicating and receiving concepts about man and nature to struggle for civil and religious liberty against authority. That is, in Shelly’s belief, poets, respecting nature and human reason, instead of the authority, should be the unacknowledged authentic legislators of the world.