Plan XVII () was the name of a "scheme of mobilization and concentration" that was adopted by the French (the peacetime title of the French (French army high command) from 1912 to 1914, to be put into effect by the French Army in the event of war between France and Germany. Though it was not "a prescribed narrative for the campaign" or battle plan, the deployment made possible a prompt invasion of Germany and/or Belgium before Germany could mobilise its reserves, simultaneous to a Russian invasion of East Prussia.