Roger Casement, who was executed by the British for treason in 1916, predicted his own downfall three years earlier when he wrote: "I fully expect to end my days in jail."
The quote is from a previously unpublished letter that has come to light in South Africa, where it is being auctioned in Cape Town.
Casement, who was a British diplomat at the time, although on leave, wrote the letter while returning from a trip to South Africa.
The eight-page letter was posted from the island of Madeira where his ship, the SS Armadale Castle, had docked during the voyage back to England, in May 1913.
The auctioneers said the letter, valued at about €4,500, had been sent by Casement to the de Villiers family in Cape Town and had remained in their possession ever since.
The letter, they said, shows that “conditions in South Africa serve as a means of crystallising Casement’s thinking on his own country”.
Casement revealed his disillusionment with the British Empire, criticises British imperial policy in South Africa and declared: “I only want to be ‘an Irishman’ – to me it is the proudest title upon Earth”.
Casement expressed sympathy for the Afrikaans (Dutch-speaking) Boers in South Africa, who, he believed, were being treated unfairly by the British.
He warns his correspondents to be sceptical of Britain's commitment to equality for the Boers and wrote: "I know quite well what the English mean by 'Equal rights'! We've had plenty of that kind of talk in Ireland but we've never seen the real thing."
He claimed that “Irishmen were being sent to jail for writing their names in Irish” and that one of his friends, “a Student of the University, got a week’s imprisonment because he refused to sign his name ‘Eamon’ in the anglicised form ‘Edmund’! And the English think they love freedom!”
Casement said: “There are a good many things I’d cheerfully go to jail for, and one is the poor old downtrodden, despised Irish language.”
He added that he was "much more than a Home Ruler" and in prophetic terms said: "I want Ireland to be restored to Europe. I want to see her again a country – a land, a nation, playing her part in European life and always as I believe, playing it just and rightly. I don't look upon her at all as a bit of English property, or as belonging to England, or as being 'owned' by anyone but herself and her own children."
The letter is for sale in an online-only auction via AntiquarianAuctions.com who said bidding would end on July 16th.
Dublin-born Casement was knighted in 1911 for his services as a British consul after publicising the atrocious working conditions of Putomayo Indians working on rubber plantations for a British company in Peru and for exposing Belgium’s exploitation and cruelty in the Congo.
He subsequently left the Foreign Office and helped to found the Irish Volunteers.
In 1916, he was arrested in Co Kerry after attempting to import arms from Germany and was sent to London and tried for treason. He was hanged at Pentonville Jail on August 3rd 1916, at the age of 51.