WWI poster: On ne passe pas. 1914 . . . 1918. Par deux fois j'ai tenu et vaincu sur la Marne. Translation of title: They shall not pass! 1914 . . . 1918. Twice have I resisted and triumphed over the Marne. A soldier standing on a battlefield wearing gas mask around his neck. Poison gas was first used in World War I. The phrase 'they shall not pass' is said to have originated with General Robert Nivelle (1856-1924) at the battle of Verdun in 1916.