An unused ticket for the launch of the Titanic in May 1911 is expected to fetch up to £25,000 at auction.
The "extremely rare" ticket would have been presented for admission to watch the ship slide down the ways as she first took to the sea.
More than 1,500 passengers and crew died when the Titanic struck an iceberg on April 14 1912.
Auctioneers say the ticket is just "one of a handful" to have survived complete with its stub and describe it as a "truly exceptional" piece of history.
The ticket, measuring 3ins by 5ins, is numbered 1,246 and is for the launch in Belfast, Northern Ireland, at 12.15pm on May 31 in 1911.
Auctioneer Andrew Aldridge, of Henry Aldridge and Son in Devizes, Wiltshire, said: "This is a truly exceptional piece of Titanic and Belfast history.
"The ticket represents the genesis for Titanic collectors, the launch of a ship is one of the first major events in a ship's life and these tickets are exceptionally rare.
"What takes this example to a different level is it is numbered so is one of literally a handful of examples known today."
A publicity booklet for the Titanic will also be sold at the auction on April 21. It is expected to fetch up to £8,000.
The brochure, bound with cord, contains five sepia plates of the liner's first class areas including a parlour suite, Turkish bath, a cafe and restaurants.
"This is one of, if not the, rarest type of Titanic brochure known," Mr Aldridge said.
"It focuses on the most exclusive areas of the ship. It is clearly aimed at first class passengers and gives us a glimpse of the opulence in these first class areas."