The musket presented by Northern Irish unionist Dr Ian Paisley to Irish Taoiseach Bertie Ahern in 2007 is to auction in Belfast.
It's valued at ?�15,000-25,000 ($22,827-38,045) ahead of the sale at Ross's Auction Rooms in Belfast on June 18.
The lot was fired in the Siege of Derry (1688-1689) and the Battle of the Boyne (1690), both of which pitted Protestants against Catholics and are two of the main flash points in the nation's sectarian past.
The gun was seen in the press as a symbol of the changes brought about by the peace process.
Paisley joked at the time: "I trust you will not allow any of these weapons to be commissioned."
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