The only known letter to have been written on board the Titanic on the day the liner struck an iceberg is to fetch as much as £100,000 when auctioned in the UK later this month.
Written by survivor Esther Hart, but never sent, the letter had been intended to be delivered to Mrs Hart's mother in Chadwell Heath in Essex at the end of what would have been the Titanic's return journey to Southampton in April 1912.
The night the letter was written - Sunday April 14 1912 - the New York-bound Titanic struck an iceberg before later sinking with the loss of more than 1,500 lives including that of Esther Hart's husband, Benjamin.
But Mrs Hart and her seven-year-old daughter, Eva, were among those rescued, with Eva living until 1996 and becoming one of the most-celebrated of the Titanic survivors.
The letter, and its envelope, were acquired around 20 years by a man who has now passed it on to Henry Aldridge & Son auctioneers of Devizes, Wiltshire, with the letter coming under the hammer on April 26.
The letter is embossed with the White Star Line flag and is headed On Board RMS Titanic and dated "Sunday afternoon".
Mrs Hart writes of how Eva had "sang (sic) so nicely" the hymn Oh God Our Help In Ages Past.
Poignantly she talked of how she and Eva were due to sing in a concert on board "tomorrow night".
Commenting on the fact that the Titanic was not supposed to roll, Mrs Hart says: "Any how it rolls enough for me." Also she adds: "Well, the sailors say we have had a wonderful passage up to now."
At the foot of the letter Mrs Hart left space for Eva to scrawl: "Heaps of love and kisses to all from Eva".
Years later, Eva recalled how her mother had found the letter in the pocket of Mr Hart's sheepskin-lined coat after the rescue.
Andrew Aldridge, head of Titanic and ocean memorabilia at Aldridge auctioneers, said: "The importance of this legendary item cannot be overstated, being the only known surviving example of its type to have been written on that fateful day, surviving the sinking, and having belonged to such a well-known survivor."
Another letter from a Titanic survivor, written on April 18 1913 and describing the hours leading up to the disaster, is to be auctioned in New York next Monday.
It was written by American Emily Ryerson and was critical of White Star chairman J Bruce Ismay with whom she had talked shortly before the sinking.
She wrote: "The strong impression which was left in my mind... was that they were speeding the ship up - to get away from the ice - & that we would probably get in late Tuesday night or early Wednesday morning.
"Mr Ismay's manner was that of one in authority & the owner of the ship & that what he said was law. If this can be of service to anyone I do not wish to be silent to seem to be protecting him."
Mrs Ryerson, from Pennsylvania, survived the sinking along with three of her children. But her husband, Arthur, was among those who died. Mrs Ryerson died in 1939, aged 76.
The letter, to be auctioned by Bonhams, is expected to fetch between £6,000 and £9,000.