This period of history was marked by turmoil, as Europe struggled to recover from the devastation of the First World War. 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 imperial government in Germany gave way to an episode of political and economic turmoil, culminated in the German hyperinflation of 1923. The second convulsion, brought on by the worldwide depression, resulted in the rise of Ultra-nationalism. In Asia, Japan became an ever more assertive power, especially with regards to China.