Steven and Michael Meloan who wrote, The Shroud (available in paperback and Kindle ebook) have an interesting Christmastide op-ed in The Huffington Post:
A mysterious peace swept across the Western Front on Christmas Eve 1914.
The Western Front, during World War I, was a system of trenches lined by wooden posts and barbed wire, stretching nearly 500 miles from the North Sea coast, south to the Swiss border. Typically, soldiers were only separated by 70 yards of "no man’s land," so close they could hear enemy voices in the lull between sniper fire and artillery rounds. Weather at the end of 1914 was brutal, relentless freezing rain had turned the trenches into a numbing river of mud. The first year of the war had already claimed roughly a million soldiers.
By Christmas Eve, British troops had received "Princess Mary Boxes," tins containing chocolates, butterscotch, cigarettes, tobacco and a picture card of Princess Mary. German troops each received a large meerschaum pipe, and fine cigars for the officers. As darkness fell, fighting along the entire front mysteriously dwindled, until finally there was profound silence. According to letters from soldiers, some German infantrymen had received tiny tennenbaum trees, and began decorating them with candles and placing them on the parapet amid the barbed wire. The British were captivated by the twinkling lights appearing along the trenches. Then they heard faint singing, Stille Nacht, Heilige Nacht. The melody was unmistakable. Some of the Brits began to sing along in English. Then Christmas greetings were shouted back and forth. Finally, a few brave soldiers arose from the trenches with offerings of food and tobacco. Before long, no man’s land was filled with soldiers greeting one another, exchanging food, trading buttons from their uniforms, and showing pictures of loved ones. Sometimes a stuffed sandbag served as a soccer ball, and impromptu games began with jackets marking the goals. Festivities and camaraderie lasted all through Christmas day.
Steven and Michael Meloan: Contagious Transcendence–The Christmas Truce of 1914