Frederick James Davies was born in Lampeter, Wales, in 1886 and joined the in 1908.
Writing home in a newly-revealed letter from the First World War he described having a “good chat with the Germans on Xmas day” during his time with the 2nd Battalion Royal Welsh Fusiliers.
“They were only fifty yards away from us in the trenches,” he wrote.
“They came out and we went to meet them. We shook hands with them. We gave them cigs, jam and corn beef.
“They also gave us cigars but they didn’t have much food. I think they are hard up for it. They were fed up with the war.”
The letter is one of a collection uncovered by Mr. Davies’ granddaughter Jane Oliver following the death of her mother, who was his eldest daughter.
The letters were recently donated to the Imperial War Museum.
In other letters Mr Davies describes how “it’s a grand sight to see the shells busting of a night, it’s just like fireworks”.
Mr Davies was invalided out of the in 1915. He shattered his spine when a trench caved in, leaving him unable to work properly in later life.
In 1919 he married and later had three children.
His youngest daughter, Audrey Trenchard, now 86, said Mr. Davies had never spoken about his experiences during World War One.
“We were so thrilled that Jane had managed to find them and keep them,” she said.
“I didn’t know about it, being the youngest I hadn’t heard any of this. It’s wonderful for me to find out about it.”
A commercial went viral with a recreation of this moment in history: