"Such a thing could not be told to the soldiers, for how would they pursue the war if they knew?" he said from his home in a village near the Cote d'Azur.
Recent research suggests that in 1914 at least 100,000 people participated in the Christmas Truce, directly or indirectly.
Soldiers climb out of a trench in World War I. The losses from such warfare were massive on both sides.
Since the start of war in August of that year, German troops had advanced west across northern France and Belgium, expecting to be victorious in six weeks. But they failed to reach Paris and by late September had withdrawn from some of the captured territory and began to dig trenches. The trench line of the Western Front, still under construction at the end of the year, eventually snaked 475 miles from the North Sea to the border of Switzerland.
Two months of fighting in Belgium that became known as the First Battle of Ypres ended in late November. Sniping and scattered efforts to capture enemy trenches continued.
Historians believe that many conditions came together in December to make the truce possible.
Losses since the start of the war were already huge. According to historian John Keegan, the French dead numbered about 306,000 (including 45,000 teenagers). The Germans had lost 241,000, and the Belgians and British each about 30,000.
Except for some Indian troops in the British Expeditionary Force, virtually all combatants came from countries where Christmas was widely celebrated. On the German side, many units were from Saxony and Bavaria, and shared Roman Catholicism with their French and Belgian foes. (German troops from those regions, at least by reputation, were also more open to breaches of military discipline than the soon-to-arrive Prussians.)
Pope Benedict XV, who took office in August, had called for a Christmas truce, which was officially rejected. In France, a prominent bishop called for peace and met with the republic's president, Raymond Poincare.
"This visit is very unusual," says Pierre Miquel, a historian of World War I and retired professor at the Sorbonne. "The cardinal immediately had to say that nobody in the clergy can speak for a political purpose."
Nevertheless, both peace and Christmas celebration were in the air. The German government had sent thousands of small Christmas trees, and candles for them, to the front. On the British side, military shipments were suspended for 24 hours so that 355,000 brass boxes embossed with the profile of Princess Mary, the king's daughter, and containing a pipe and tobacco products, or candy, could be delivered.
The greatest incentive, though, was the simple misery of the moment -- almost continuous rain, foul and muddy trenches, daily killing, and dead bodies in view.
"You couldn't bury the dead because if you tried, they'd shoot you," says Michael Juergs, former editor of Stern magazine and the author of "The Small Peace in the Great War." "So you always had to look on the no man's land and you can see your own future, which is to lay dead there."
Merging the Lines
The history of the Christmas Truce is essentially a compendium of anecdotes gleaned from letters, diaries, oral memories, and, to a lesser extent, official military records. The most complete accounts in English are "Christmas Truce" (1984), written by British authors Malcolm Brown and Shirley Seaton, and "Silent Night" (2001) by Stanley Weintraub, an American. Juergs's book has not been translated from German.
A few generalizations are possible.