A painting thought to be the earliest likeness of Gulliver's Travels author Jonathan Swift is to be sold in an online auction.

Swift is believed to be only sixteen years old and a student at Dublin College in the painting, which is estimated to fetch between £30,000 and £50,000.

The painting, which is attributed to the Irish artist Thomas Pooley, will be sold live online from Edinburgh by fine art auctioneers Lyon & Turnbull on Wednesday, May 18.

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There are few images of the celebrated Anglo-Irish author, whose works include An Argument Against Abolishing Christianity and A Modest Proposal.

Thought to have been painted around 1682, it is coming to auction for the first time in 200 years.

HeraldScotland: Dominic Somerville-Brown, rare books specialist, takes a closer look at the Jonathan Swift portrait. Photo by Stewart Attwood.Dominic Somerville-Brown, rare books specialist, takes a closer look at the Jonathan Swift portrait. Photo by Stewart Attwood.
Nick Curnow, head of fine art at Lyon & Turnbull, said: "This is a remarkable painting of a literary giant of whom few likenesses exist.

"Swift is a very self-assured sitter for a young man and the work has a presence and immediacy that so many 18th-century portraits lack."

The work was acquired by Thomas Percy, Bishop of Dromore, County Down, in 1801, who recorded it as "a small portrait of Dean Swift".

First exhibited at South Kensington in 1867, it then drifted in and out of public view for the next hundred years.

In 1898 Sir Leslie Stephen, writing in the Dictionary of National Biography, declared "the present whereabouts of this portrait is unknown".

It reappeared around 1967 in the collection of a descendant of Thomas Percy and at this time it came to the attention of Swift scholars and was attributed to Pooley.

The artist painted many high society figures in Ireland during the second half of the seventeenth century and at the start of eighteenth century, contributing to the theory that Swift was the illegitimate son of his benefactor, Sir John Temple.

HeraldScotland: Jonathan Swift as a student at Dublin CollegeJonathan Swift as a student at Dublin College
It was shown in an exhibition at the National Library of Ireland in 1999.

Dominic Somerville-Brown, rare books specialist at Lyon & Turnbull, said: "Swift has an enduring hold on readers' imaginations and an indisputable place in the literary canon.

"However, his legacy is not matched by a profusion of images, especially given the era in which he lived.

"This portrait being auctioned is therefore very exciting and I will be on tenterhooks when bidding begins."

The portrait is being auctioned as part of Lyon & Turnbull's Five Centuries: Furniture, Paintings & Works of Art sale.