The family of an officer who chose to go down with the Titanic have appealed for help to return to his home town a letter he sent from the doomed liner.
The two page personal note Dr John Edward Simpson wrote to his mother days before the ship sank is due to fetch at least 50,000 dollars (£31,500) when it is sold at a New York auction house at the start of next month.
His relatives, who say they cannot afford to bid for the valuable artefact, desperately want to see it brought back to Simpson's native Belfast, where the Titanic was built, to be put on museum display.
Fearing it could be snapped up by a private collector and lost from public view forever, they are hoping a benefactor can step in.
"We're at a point now where the family can't afford to buy it and it would be great if a donor or benefactor could be found who would purchase and return it to Northern Ireland for public display," said his great nephew Dr John Martin.
According to eyewitnesses who survived the 1912 disaster, Dr Simpson, 37, the assistant surgeon on board, stood with fellow officers on the deck of the stricken vessel as it went down, resigning themselves to their fate, making no attempt to board the lifeboats and instead calmly helped others to safety.
Dr Martin explained that the letter had been passed down through several generations in the family and the plan was always to have it placed in a permanent Titanic exhibition in Belfast.
But he said 15 years ago Dr Simpson's 81-year old daughter-in-law gave it to a Titanic enthusiast in Holland in the hope it would go on display.
However, what happened to the letter after that remains a mystery to the family and Dr Martin said relatives have always regretted its loss.
He said they thought it was gone for good until they heard it was to be sold at Philip Weiss Auctions in New York city.
The retired Belfast doctor said the letter should be placed somewhere the people of the city could see it.
"There aren't that many actual Titanic artefacts which relate specifically to Belfast and he was as far as I am aware the only serving officer on Titanic who was a native of Belfast," said 63-year-old Dr Martin.
"And the letter was one of the last objects to leave the ship before the sinking - all of those things really make it quite a unique artefact."
The letter, dated April 11 1912 and written on notepaper headed RMS Titanic, was brought ashore at Cobh, Co Cork (then called Queenstown) before the ship set sail for America. It was dispatched to his mother Elizabeth living on Belfast's Dublin Road.
In it the married father of one, who was then based in Liverpool, said he was tired but settling into his cabin well.
He had worked on the Titanic's White Star Line sister ship the Olympic for a year previously and observed to his mother that the accommodation on board his new vessel was larger.
Dr Simpson also complained that he had found one of his trunks unlocked and 5 or 6 dollars had been stolen from his pocket book.
The surgeon, who treated second and third class passengers, signed off: "With fondest love, John."
Three days later he died along with 1,500 others after the ship struck an iceberg.
Dr Simpson's story will form part of the new £90 million Titanic Belfast visitor attraction that is opening in Belfast next month ahead of the 100th anniversary of the sinking in April.
Dr Martin, who with his sister Kate Dornan and cousin Dr Denis Martin is appealing for a benefactor to come forward, said the letter provided a rare insight into the life of one of the ship's officers.
"There are references within the letter which give a bit of humanity to the man who died and he did die bravely," he said.
"It puts a human face on what could be another statistic."
Dr Simpson was a contemporary of Titanic designer Thomas Andrews at Royal Belfast Academical Institution - a plaque commemorating both men's bravery is displayed in the school.
He went on to study medicine at Queen's University in the city before moving to London to become a GP.
Dr John Martin said the stories of his great uncle's last moments were a great source of pride for the family.
One account, contained in a letter written after the disaster by 2nd officer Charles Lightoller, who survived, is going on sale in same auction in March.
He described encountering the assistant surgeon walking along the deck with other officers.
"They were perfectly calm in the knowledge they had done their duty," he wrote.
He continued: "We exchanged the words, 'Goodbye, old man.' This occurred shortly before the end and I am not aware that he was seen by anyone after."
The letter written by Mr Lightoller is set to be sold for 20,000 US dollars.