Nelly Ayres received a telegram from the British Army in October 1917 telling her that her husband Arthur had been made “non-effective by death”.
Sapper Ayres, of the Royal Engineers, died in a military hospital near Boulogne in France, three weeks after being wounded at Passchendaele, as he helped care for injured comrades.
A century later, his paternal granddaughter Sue Patterson was among the 4,000 descendants of those who fought who are attending a memorial service for the fallen at Tyne Cot Cemetery near Ypres, where so many of the dead are remembered.
Some of those who have come have relatives buried in visitable graves, while thousands whose bodies were never recovered are remembered in names etched into plaques on the walls of the largest Commonwealth cemetery by the number of the interred in the world.
Mrs Patterson said a letter from her grandfather’s commanding officer had revealed that after being wounded himself at Passchendaele on October 1 1917, he was helping bandage injured comrades when he was wounded again by a second artillery blast.
He died in hospital 21 days later, leaving Nelly a widow after nine years of marriage, with four small sons.
Mrs Patterson, 56, who lives in Leeds, said Nelly had been “greatly comforted by the letter”.
She said: “The four boys and Nelly were very close and very poor, they were known not to have shoes.
“She never remarried, she lived for her sons.
“My father was a very peace-loving man, he was not a pacifist, he just thought it should have been the war to end all wars.
“None of the boys ever came to see Arthur’s grave. They said it would be too sad for them.
“But their children, and Arthur’s great-grandchildren, have come out to honour their grandfather and great-grandfather.”
The descendants will join senior royals and politicians including Prime Minister Theresa May later on Monday to pay tribute to their relatives and the thousands of others who fell at Passchendaele.