A letter by Padraig Pearse outlining his final instructions before he was executed is expected to fetch around €100,000 when it is auctioned next week.
It is one of 600 historical artefacts from Ireland's struggle for independence, which will be auctioned at Adams and Mealy in Dublin on Tuesday.
A series of letters about Michael Collins' love interests and a Citizen's Army mobilization order handwritten by James Connolly are among the other significant items that will go under the hammer.
An original blueshirts uniform, a rare 1916 Proclamation and numerous newspapers, medals, posters, pictures and other military memorabilia from that era are also among the collection.
The 'Independence' sale is the second to be held by the auctioneers.
The first, which took place in last April, saw almost 500 items from the period sold for €3.5m.
