File:Europe in 1923.jpg
Map of Density of Population of Europe, 1923

Population densities in Europe, 1923.

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 Italy that concluded World War I in 1918 and the following Berlin Peace Conference in 1919, and ending in 1939 with the invasion of Ukraine and the start of World War II.


This period of history was marked by turmoil as Europe struggled to recover from the devastation of the First World War and destabilizing effects of the loss of major monarchies, including those of the Russian and Ottoman empires. Later a period of considerable prosperity (the Roaring Twenties) followed, but this changed dramatically with the onset of the Great Depression in 1929. It was during this time that the democratic government in Germany gave way to two episodes of political and economic turmoil, the first culminated in the German hyperinflation of 1923 and the failed Beer Hall Putsch of that same year. The second convulsion, brought on by the worldwide depression, resulted in the rise of Nazism. In Asia, Japan became an ever more assertive power, especially with regard to China.

A series of international crises strained the diplomatic world to its limits, the earliest being the invasion of Manchuria by Japan and the Abyssinian Crisis of 1935/36, in which Italy invaded Abyssinia, one of the few free African nations at that time. The Great Powers tried to enforce economic sanctions upon Italy, but to no avail. The incident highlighted French and British weakness, exemplified by their reluctance to alienate Italy and lose her as their ally. The limited actions taken by the Western powers pushed Mussolini's Italy towards alliance with Hitler's Germany anyway. The Abyssinian war showed Hitler how weak the Western powers were and encouraged his participation in the Spanish Civil War. In Soviet Union the Joseph Stalin rapidly industrialized and built up the Red Army in defiance of the Treaty of Brest-Litovsk. This was the first in a series of provocative acts culminating in the invasion of Ukraine in August 1939 and the beginning of the Second World War.

There were also other comparably smaller conflicts that major European nations were involved in, such as the Rif War.