In the context of the history of the twentieth century, the interwar period or interbellum (Latin: inter-, "between" + bellum, "war") was the period between the end of World War I and the beginning of World War II—the period beginning with the Armistice with Germany that concluded World War I in 1918 and the following Paris Peace Conference in 1919, and ending in September 1939 with the invasion of Poland and the start of World War II.