The great age of Romantic Poetry was from the middle of the eighteenth until the early nineteenth century. The big six who exemplified the age were Wordsworth, Coleridge, Keats, Shelley, Byron, and Blake.
This was the period when the lofty poetic diction of the Augustan Age was largely replaced by straightforward language. A major influence was the program set forward in the Lyrical Ballads authored jointly by WilliamWordsworth and Samuel Taylor Coleridge. We could summarise the great Romantic qualities as an enduring sense of wonder, a great love of beauty, marked melancholia, and a keen sensibility, with the rich splendour of Imagination enfolding poetic expression. The theme of themes was Nature.
Nature offered not only beauty, but solace in its contemplation and an invitation to the poet to find significance even it its trifling manifestations. Many poets discovered a religious meaning too in Nature.
Love of liberty and hatred of tyranny flows in the poetry of the Romantic poets. They cherished individual freedom as a condition of romanticism. Their voices championed the cause of liberty domestically and in other lands.
Running through their themes is a philosophical notion that the poet should live plainly, associate with people, and constantly keep in mind the high moral purpose of their writings.
The expressions of human love are varied. In Keats, love is a sensuous, earthly passion and his expressions invoke an ardour missing in such poets as Wordsworth and Coleridge. Coleridge and Wordsworth are more for spiritual bliss.
Intense subjectivity and melancholy, are characteristics of romanticism, and no poet in the Romantic era escapes it. Though Wordsworth’s definition of poetry is often quoted (“emotion recollected in tranquility“), it hardly qualifies the poetry you find in much of Keats‘ love sonnets, for example, To Fanny:
O! let me have thee whole,—all—all—be mine!That shape, that fairness, that sweet minor zestOf love, your kiss,—those hands, those eyes divine,That warm, white, lucent, million-pleasured breast,
Love and death are closely associated in the minds of the Romantic poets.
Perhaps after Nature the chief source of inspiration for the Romantic poets was their belief in the creative powers of the Imagination. Some like Blake founded whole imaginative universes, peopled by personages of mythical names. Others like Coleridge could enter dream-like states of bliss and describe their fancies in such alluring language that readers would be mesmerised and suspend their own reality so as to partake in what the poet had on offer, which was far more brilliant. Keats‘ imagination was no less sumptuous and inspiring, as may be seen in such a lovely poem as Ode on a Grecian Urn. But even in a lesser poem, On Leaving Some Friends At An Early Hour you can hear the note:
Pink robes, and wavy hair, and diamond jar,And half-discover’d wings, and glances keen.The while let music wander round my ears,And as it reaches each delicious ending,Let me write down a line of glorious tone,
Some poets of the same era writing in other countries are also gathered under the same umbrella, e.g. Edgar Allan Poe and Pushkin. There are also a number of other poets in England and Scotland considered to be in this category, including women poets. For this wider collection one may read the Wiki entry on Romantic poetry. The British Library has an essay by Stephanie Forward on the key ideas and influences of The Romantics. There is a more varied collection of essays on Romanticism from the British Library.