One of the chief contributing causes of the Second World War was the Treaty of Versailles (June, 1919), that officially ended the First World War. Its main terms were surrender of ALL German colonies in Africa and the Far East, which would be mandated to Britain, France, Belgium, South Africa, Japan and Australia. This led to a re-distribution under a series of mandates – for example, the return of Alsace-Lorraine to France, the cession of Eupen-Malmedy to Belgium; plebiscites to be held in Northern Schleswig, the cession of Prussian Poland, parts of East Prussia and Upper Silesia to Poland; the cession of Danzig (now Gdansk) to be administered by the newly invented (and doomed) League of Nations; the cession of diminutive areas around Hultschin to Czechoslovakia; the cession of Memel (which was eventually annexed by Lithuania); the occupation of the Saar by the French; a demilitarization of the Rhineland, accompanied by allied occupation during fifteen years; the payment of an enormous sum in reparations ( £6,500 million in 1921: later Adolf Hitler would claim that this sum, demanded of a defeated Power by France and Belgium, was a veiled attempt to crush both the German spirit and the German economy); the limitation of the German Army to 100,000 men with no general staff, no conscription, no tanks, no heavy or light artillery, no poison gas supplies, and no aircraft or zeppelins. The German Navy was limited to ships under 10,000 tons (no battleships or cruisers then), no submarines and no Navy airforce.
The Treaty did not allow any union between Germany and Austria (the Anschluss); it also declared Germany responsible for causing the war, and made provision for an official trial of the deposed Kaiser and other war leaders.
Large areas of public opinion in Britain and France claimed that the terms of the Treaty were not harsh enough. Congress in the United States, however, went the other way, and refused to ratify the Treaty. Germans of all classes rejected the ‘war-guilt’ clause, and this continued to rankle with them until Hitler became Chancellor. In 1933 he refused to consider himself bound by the Treaty, and promised Germany total revenge. Ex-Kaiser Wilhelm II was never brought to trial. Senior officers found ways after 1919 of getting round the disarmament clauses.
When the draft Treaty was ready, German representatives were told they were required to sign it without negotiation.
There were more Treaties to come: St. Germaine-en-Laye (September, 1919) was between the allied powers and the new Republic of Austria, which had to recognise the independence of Czechoslovakia, Poland and Hungary. Austria lost Eastern Silesia, the Trentino, South Tyrol, Trieste and Istria. Austria, like Germany, was required to pay reparations during a period of thirty years.
Trianon (June 1920) established the new Republic of Hungary, whereby three-quarters of her old territories (ie. all non-Magyar lands) were lost to Czechoslovakia, Romania and Yugoslavia. The principle of reparations was again accepted.
Neuilly (November 1919) was a treaty made with Bulgaria: some territory was lost to Yugoslavia and Greece, but on the other hand some was gained from Turkey. A figure of £100 million in reparations was agreed upon (but never paid). These four Treaties were ratified in Paris in 1920.
A fifth Treaty (Sèvres, August 1020) was between the Allies and the old Ottoman Empire but was never implemented as it was followed by the final disintegration of the empire and the creation of the New Republic of Turkey by Mustapha Kemal Atatürk. All this was taken into account in the forming of a sixth treaty (Lausanne, July 1923), whereby Palestine, Transjordan and Iraq were mandated to Britain (thus causing interminable conflict), and Syria to France. Turkey regained Smyrna from Greece (leading to a continuing hatred between both countries). The Dardanelles Straits were de-militarized, and it was decided that Turkey would pay no reparations. This last lunacy caused widespread dissent, especially among the nations of the Arab League which had suffered invasion by the Turks during the War – and caused Laurence of Arabia (who had fought the Turks tooth and nail in the desert) to retire from public life in disgust, change his name (twice), and live as a semi-recluse in his Dorset cottage at Clouds Hill.