Father and son Fred and George Docksey both broke the rules in order to fight in the First World War.
Oakworth resident Fred was too old to go to the frontline, while his teenage son was too young.
Fred, who was 47 when he enlisted in July 1915, survived the war and went on to live for another 16 years.
But George, who was 17 when he joined up the following month, was killed in the final year of the conflict.
Fred was born in Sea-combe, Cheshire, in 1868, and at the age of 22, was living in Lower Providence, Oakworth, with his wife, Ellen.
The pair had nine children, with George becoming one of only six who were still alive in 1911.
Fred enlisted in Skipton in 1915 after previously serving three years with a volunteer battalion.
By the end of his four years’ army service, he was in a Pioneer Battalion of the Royal Engineers working on quarries and roads, and was discharged suffering from rheumatism.
Meanwhile, George had enlisted in August 1915.
Men of Worth Project founder Andy Wade said George was just 17 years old when he joined up, using the name John Docksey.
Mr Wade said: “Local rumour is he tried to enlist locally on more than one occasion and got knocked back each time, so he went to Skipton where they let him in.”
George, a private in the Prince of Wales’ Own West Yorkshire Reg-iment, was posted missing in March 1918, and later declared dead.
A Keighley News report from that spring mentioned George’s father was serving in France with the Royal Engineers, and an unnamed brother had been in France with the Royal Air Force.
George Docksey has no known final resting place, but he is remembered on the war memorial under his correct name and the Arras Memorial under his alias of John.