An extremely rare 99-year-old poster announcing the formation of a provisional government for Ulster is set to go under the hammer at auction.
The copy of the 1913 proclamation by Edward Carson and other leading unionists in the midst of the Home Rule crisis is thought to be the only one of its type left in existence and is expected to go for a potential £30,000.
An unnamed private collector in Northern Ireland has asked Bonhams auctioneers in London to put the artefact up for sale on June 12.
The Ulster Proclamation of Provisional Government signalled the intent of unionists to form their own administration in the nine northern counties of Ireland if Westminster handed powers to a nationalist parliament in Dublin.
It was issued the year after almost half a million people in Ulster signed either the Solemn League and Covenant or Declaration in opposition to Home Rule and as tens of thousands joined the original Ulster Volunteer Force in preparation to resist the move by force.
The crisis was overtaken by the outbreak of World War One and a nine-county government was never formed.
The Irish War of Independence in the wake of the Great War eventually saw the island partitioned in 1921 with the formation of a six-county Northern Ireland still under British rule and an independent southern state.
The proclamation poster, dated September 24, 1913 and printed in blue, is to be auctioned at a Bonhams sale of books, maps, manuscripts and historical photographs. It is estimated at £20,000 to £30,000.
Andrew Currie from Bonhams said: "This is a poster that was put up on walls, so you can image with rain and the passage of time and other things, few survived. We believe this is the last one."
He predicted the item would attract plenty of bidders. "It is a rare historical document relating to the history of a country so I would expect a lot of interest in it," he said.