Portfolio: Monty Guilford

My grandfather Monty never talked about the war. Or if he did, it wasn't to us, his family – and he was a man who loved to chat. Well, we knew that he had been an Anglican chaplain on the Western Front, travelling in one day in September 1916 from Mitcham in Surrey to within the sound of the guns of the Somme. Like all padres at that time, he had had almost no training, and no one told him what he should be doing. Some of the most vocal bishops and generals wanted their padres to be preaching a Holy War. Others – and this is the slur that stuck, thanks to Robert Graves' damning indictment in his 1929 autobiography Good-Bye to All That – thought that the padres were a time-wasting bunch of pusillanimous skivers.

But all that his family knew was that Monty had stayed and that, at the Battle of Cambrai in 1917, he had won the Military Cross. We also knew, although none of us remembers how, that at some point over the two years of gas, mud, butchery and numberless burials, Monty had lost his faith in a benign, rational God. Who, I guess, wouldn't?

There it might have ended except that, three years ago, my son was doing a school project on the First World War and I told him I thought his great-grandfather might have left a few interesting bits and pieces in a trunk in the attic. Together we dragged the disintegrating thing down, popped it open and watched as the story of Monty's war poured out in front of us.

There were letters and newspapers, trench maps and postcards to his baby daughter. We found his wartime sermons and, thrillingly, his diary. There were mementos to his dead friends and family; medals, poems and cartoons; and the orders for him to hold vigil with Private Joseph Bateman on the eve of his execution for desertion. At the bottom of the trunk we found hundreds of photos, many startlingly clear, of tanks and graves, of the chapel he dug in the trenches and of his friends goofing around. In short, we found a way to cut through to the real story of what my grandfather did in the war – and how, when he returned home, he found his way back to his faith.

'To War With God: The Army Chaplain Who Lost His Faith', by Peter Fiennes, is published by Mainstream, priced £17.99