A letter of surrender written by Patrick Pearse will be auctioned in Dublin in December.

The handwritten, one-page letter, written on April 30, 1916, has an estimated value of up to €1.5 million ($1.7 million) — the highest estimate ever given to any art work or historical item offered for auction in Ireland, the Irish Times reports.

Adam’s Auctioneers described the letter as “the most significant Irish document to be offered for sale.”

Auctioneer Kieran O’Boyle said it was “the last official letter Pearse wrote, three days before his execution by firing squad on the morning of May 3rd 1916”.

The letter, which Pearse wrote in his prison cell at Arbour Hill jail, reads: “‘In order to prevent further slaughter of the civil population and in the hope of saving the lives of our followers, the members of the Provisional Government present at headquarters have decided on an unconditional surrender, and commandants or officers commanding districts will order their commands to lay down arms. P.H.Pearse, Dublin, 30th April 1916. ”

Pearse who had surrendered to the British outside the GPO the day before the letter was written, on April 29th, was asked to write the letter to persuade a group of rebels holding out in the Four Courts to surrender. 

Fr Columbus, a friar in the Capuchin Order, hand-delivered the letter to the rebels, who ceased hostilities and surrendered after reading it. 

The friar held on to the letter, which resurfaced again in 2005, when it was bought from Adam’s at auction by an unnamed client for €700,000. The letter is now being sold by the same client.

O’Boyle said the owner wished to remain anonymous.

The highest price ever reached at auction for an item of Irish historical memorabilia was €760,000 for the handwritten first draft of A Soldier’s Song/ Amhrán na bhFiann, the Irish national anthem, signed by author Peadar Kearney. The item sold to an anonymous bidder in 2006.

The highest price paid for an auctioned art work in Ireland was €1 million for A Fair Day, Mayo, a painting by Jack B Yeats, which sold in 2011.

The Imperial War Museum in London holds the official surrender document of the Rising, which was typed by the British and signed by Pearse on April 29, 1916. The National Museum of Ireland has two other surrender letter Pearse wrote to other garrisons in Dublin.