A rare Fenian flag is expected to fetch up to $70,000 (€50,000) when it goes up for auction later this month.
The 1867 Fenian Rising Flag was commissioned by Willie Condon, who was a leading Fenian member from Co. Cork.
The flag was flown at many demonstrations from the 1860s through to the Land League campaigns of the 1880's. It was placed under an old flour sack during the Black and Tan raids.
According to Ian Whyte, managing director of the auction house on Molesworth Street many valuable historical items were hidden away but from time to time have reappeared.
"There would still be stuff discovered. During the Black and Tan period, during the War of Independence, a lot of stuff was hidden away," he told the Irish Independent.
Mr Whyte said he wasn’t aware of any similar flag in private ownership but had seen a number in national institutions.
Other items to go under the hammer include a collection of more than 80 original newspaper photographs dating from 1916 to 1923 and a Viking penny dating from the time of the Battle of Clontarf both of which are expected to generate interest.
POLL: Who won the first presidential debate, Clinton or Trump?