A retired Italian doctor has revealed for the first time how he invented a fictitious disease which fooled the Nazis during World War II.
Mr Sacerdoti invented "K Syndrome" to save lives when he was just 28
The trick of prescribing Jews with a mysterious illness terrified the Nazis and saved 45 Roman Jews.
Dr Vittorio Sacerdoti has told his remarkable tale on the 60th anniversary of liberation of Rome.
He worked from a small and ancient hospital based on an island in the River Tiber.
From his flat in the Jewish ghetto where he still lives, he told the BBC's Guto Harri in Rome that he still remembers the day the Nazis turned up at the ghetto to take away his fellow Jews.
Just 28 years old at the time, he used courage and ingenuity to save 45 people from certain death.
The doctor still lives in the Jewish area of Rome, minutes from the hospital
As other Jews were being rounded up, Dr Sacerdoti admitted anyone who could reach the hospital as patients - and diagnosed them with a dangerous disease.
"We would write on their medical forms that the patient was suffering from K Syndrome," he said.
"We called it K after the German commander Kesselring - the Nazis thought it was cancer or tuberculosis, and they fled like rabbits."
K Syndrome saved his cousin, Luciana Sacerdoti, who was just 10 years old.
"The day the Nazis came to the hospital, someone came to our room and said: 'You have to cough, you have to cough a lot because they are afraid of the coughing, they don't want to catch an awful disease and they won't enter'."
A detailed testimony has now been taken by the Shoah foundation belonging to American film director Steven Spielberg.
But there is growing pressure for a larger exhibition closer to home. A small exhibition exists in Rome's synagogue, but there is very little to remind a new generation of the worst ills of the past.
As Tulia Zevi told our correspondent: "We are also what we remember. We are made of our memories.
"A person who lives only in the present and has not a full consciousness of what lies behind his back is not fully human."