His gravestone describes him as "the Northamptonshire Peasant Poet", but John Clare, who died 150 years ago this month, was much more than that.

His life spanned the era of the great Romantic poets. Wordsworth and Coleridge had proclaimed that modern poetry should speak with the voice of the rural poor, a class to which, unlike Clare, they did not themselves belong. Clare and John Keats shared the same publisher but whereas Clare grew up intensely close to nature, Londoner Keats did not. Indeed, Clare said that Keats “often described nature as she appeared to his fancies and not as he would have described her had he witnessed the things he described”.

Clare was born in the village of Helpston, near Peterborough, to almost illiterate parents. He attended a local church school until he was 12, after which he worked at various jobs, including agricultural labourer, pot boy, gardener and lime-burner.

As a young adult, he fell in love but the young woman’s father, a well-off farmer, forbade her from seeing him. He wrote the poem “First Love” about the experience. “I never saw so sweet a face / As that I stood before. / My heart has left its dwelling-place / And can return no more.”

Influenced by Scottish poet James Thomson's The Seasons, he began to write poetry, and his first collection, Poems Descriptive of Rural Life and Scenery, was published in 1820, when he was 27. It was well received and Village Minstrel and Other Poems followed a year later.

His poem “May” gives a flavour of his nature poetry. “Come queen of months in company / With all thy merry minstrelsy. / The restless cuckoo absent long / And twittering swallows’ chimney song / And hedgerow crickets’ notes that run / From every bank that fronts the sun.”

He married Martha Turner in 1820 and they had seven children over time. Struggling to support his large family and torn between the world of literary London and his humble rural life, he began to suffer increasingly from poor health.

The countryside to which he was so close and the nature about which he wrote so lovingly and with such a keen eye underwent massive upheaval in the early 19th century. Acts of Enclosure from 1809 to 1820 gave landowners permission to fence off the fields, heaths, woods and commons upon which many of the rural poor depended for a living. Ancient trees and hedges were uprooted, rivers were canalised and the fens were drained.

This destruction of a centuries-old way of life and the changes that it brought distressed Clare greatly. “Inclosure came and trampled on the grave / Of labour’s rights and left the poor a slave … / And birds and trees and flowers without a name / All sighed when lawless law’s enclosure came.”

Various suggestions have been made to account for Clare's loss of mental health: manic depression, bipolar disorder and malaria are some of them. No doubt to have to witness the loss of a way of life that he had known since childhood also contributed. The death of Byron in 1824 also led to a downturn in the market for poetry and Clare's The Shepherd's Calendar (1827) did not do well.

Various efforts were made by patrons to help him and his Rural Muse (1835) was reviewed favourably but that was not enough to help him support his family, and bouts of heavy drinking increased as he became more dissatisfied with his life. He agreed with his publisher's suggestion that he enter a private asylum in Epping Forest in 1837.

Apart from a brief period of about six months, sadly he spent the rest of his life in medical asylums. One of his delusions was that he was a reincarnation of Shakespeare and also Byron.

He wrote what is possibly his most famous poem, “I Am”, while in medical care.

“I am – yet what I am none cares or knows; / My friends forsake me like a memory lost; / I am the self-consumer of my woes …”

The poem concludes with a deeply moving final stanza: “I long for scenes where man hath never trod, / A place where woman never smiled or wept, / There to abide with my creator, God / And sleep as I in childhood sweetly slept; / Untroubling and untroubled where I lie, / The grass below – above the vaulted sky.”

Clare’s work became largely forgotten in the later 19th century but there was a revival of interest in the 20th century and he came to be seen as one of the great English Romantic poets.