WWI started with a french declaration of war against the German State due to rising tensions including the creation of the german state not long before and the German state's annexation of Luxembourg. With the french declaration of war came the british also declaring war as well as the polish. the Austrians came to the aid of the Germans and in the span of a couple days many of the worlds nations were at war. The germans attempted an assault on france and on the Soviets later on while other countries were mainly on the defensive in the Imperial Powers. By the end of the war Austria-hungary had nearly fallen leading to German annexation of Austria.