While the existence of a 1914 Christmas Truce during the First World War is confirmed, evidence of later Truces has been sketchy to nonexistent. Until now.
From a letter written by a Canadian soldier, recently found by an historian.
According to the letter, written December 30, 1916, another truce took place in 1916:
Here we are again as the song says. I had quite a good Xmas considering I was in the front line. Xmas eve was pretty stiff, sentry-go up to the hips in mud of course. I had long rubber boots or waders. We had a truce on Xmas Day and our German friends were quite friendly. They came over to see us and we traded bully beef for cigars. Xmas was "tray bon" which means very good.