The main factor that pushed the Allies to victory was the entry of the United State into the war in 1917.
In 1917 had not been a good one for the Allies.
On September 29, 1918, General Ludendorff informed German leaders that the war was lost.
By April the German troops were within about 50 miles of Paris
The German attack was launched in March 1918.
David Lloyd George prime minister of Great Britain, had won a decisive victory in elections in December 1918. His platform was to make the Germans pay.
The Treaty of Versailles with Germany, signed at Versailles near Paris on June,28 1919.
In 1919, representatives of 27 victorious Allied Nations met in Paris to make a final settlement of the Great War.
On January 25, 1919 the conference accepted the idea of a League of Nations.