Catholic Action are groups of lay Catholics who advocate for increased Catholic influence on society. They were especially active in the nineteenth century in historically Catholic countries under anti-clerical regimes such as Spain, Italy, Bavaria, France, and Belgium.

Erich Klausener was a German Catholic politician and Catholic martyr in the "Night of the Long Knives", a purge that took place in Nazi Germany from 30 June to 2 July 1934, when the Nazi regime carried out a series of political murders.