World War I, known to the generation that lived through it as the Great War, shaped the history of the twentieth century. In the Allied countries, the conflict began in August 1914 with a rush of patriotism and the expectation that the fighting would be brief. Victory, it was believed, was but a few weeks or months away. It would all be over by Christmas. This optimistic forecast, along with much else, was soon shattered by terrible events. Instead of being short and glorious, the war turned out to be long and unremitting. In France, the contrast quickly degenerated into trench warfare, a savage form of combat that tested the resolve of the rival armies and produced casualties on a hitherto unimaginable scale. As death and destruction piled upon death and destruction, there seemed to be no way out, until, finally, the Allies were able to gain the advantage and force surrender.