It’s a famous story: Christmas Eve, 1914. World War I was raging, opposing British and German forces were locked in a muddy, bloody battle, with the casualties of war littered in the no-man’s-land between their trenches. Despite the pleas of the pope for a Christmas ceasefire, none had been ordered, and the battle went on. Until…After a startling and confusing time of silence, a Christmas hymn rose from the side of the German forces. It was a tune the British knew well. Stille...