The violin was made by Matteo Goffriller in Venice in 1698
A £10,000 reward is being offered for the return of a valuable 17th Century violin which was left on a train.
Robert Napier, from Wiltshire, had just had the 1698 Venice-made Goffriller valued by a London dealer at £180,000.
He got off a Paddington to Taunton train at Bedwyn on 29 January with the family heirloom still on board.
"It was just one of those terrible moments when I realised, as the train was steaming off, that I had left it on the train," he said.
Despite raising the alarm soon after and a search being made of the train at Taunton station, the violin has not been found.
"I put it on the luggage rack above my seat and when I got to Bedwyn, got off the train and I simply left it. I had my briefcase and coat, how I normally travel," said Mr Napier.
"I've relived the moment. I think when I put it on the luggage rack I thought I couldn't possibly forget it, and I didn't want to appear different. I was trying to behave normally."
Mr Napier jointly owns the instrument with his two brothers and two sisters, who inherited it from their mother, Elizabeth Hunt, from Wellington, Somerset.
During WWII, she performed with it entertaining troops as a member of an ensemble called the Ebsworth Quartet.
Later, she took the violin on travels abroad to India, Africa and Germany.
The missing Goffriller, together with a bow stamped R Sartory, were in a rectangular case with a brown cover.
Insurance company Allianz has offered a reward of up to £10,000 for the return of the instrument.