In 1938, a campaign was started by local Selbstschutz in the Czechoslovakian Sudetenland in order to subjugate the local Czechs prior to the Munich Conference. During the Invasion of Poland of 1939, a number of similar units conducted sabotage actions directed by the emissaries trained in Nazi Germany. These groups were officially merged into one organization, the ethnic German Volksdeutscher Selbstschutz (Self-Defense Force) of more than 100,000 men.