William Blake was a poet who was not very well recognized during his lifetime. It was not until his sixties when his work began to receive credit as leading a new literary movement in England at the time that was really triggered by William Wordsworth and Samuel Taylor Coleridge who were both much younger than Blake and of a superior social class. In his younger years, William Blake's poetry was written off as lunacy by most of his contemporaries, and although he is recognized now as the 'grandfather' or the Romantic period, he was in fact much older and far removed from that time.
That being said, the reason Blake is associated with Romanticism is because of his ardent support of the French Revolution and all forms of anti-establishment radicalism. Blake was an untiring rebel who verbally and poetically fought hard against all constrictions of his time--religious, social, sexual, and literary. His poems transmute clearly all the burring issues and events of his day and touch on issues such as the American War for Independence, the French Revolution, Colonialism and the expansion of Empire, Slavery, and finally the Industrial Revolution. Through Blake's work, the reader can deduce his passion and vision that social rebellion against these injustices would serve as an apocalyptic turning point in the history of humankind, destroying the old, decaying order of oppression and presaging the redemption of humanity.
The poems of William Blake reinterpret the spiritual history of the human race from the fall from Eden to the beginning of the French Revolution. Blake believed in the correspondence between the physical world and the spiritual world and used poetic metaphor to express these beliefs. In his poetry, we hear a man who look's for mankind to salvage his redemption from oppression through resurgence of imaginative life. The power of repression is a constant theme in Blake's poems and he articulates his belief in the titanic forces of revolt and the struggle for freedom against the guardians of tradition.
What is important to keep in mind when discussing or reading Blake's poetry is that a lot of his poems were accompanied with some sort of illustration, painting, or in the case of the prophecies and songs, copper plates. It is difficult to fully grasp the poet’s intentions without having access to the artwork married to the poem.
Additionally, his earliest work, "Poetical Sketches," which is a collection that a lot of the poems discussed here are taken from, shows dissatisfaction with the reigning poetic tradition and his restless quest for new literary forms and techniques. Eventually, Blake's genius would blossom and his thinking began to be articulated in giant forms, leading to the creation of complete mythology and extremely symbolic epics.