Before World War II, Forster had tried and failed to gain control over the organisation of the irredentist activities of the ethnic German population in the Polish Corridor, neighbouring Freie Stadt Danzig, which was created in 1920 by the Treaty of Versailles; rather it was the SS-dominated "Volksdeutsche Mittelstelle" that won control. With Forster and Himmler engaged in a power struggle, this rendered the (ethnic) Germans suspicious of Forster. When these territories were annexed after the Invasion of Poland and they became Reichsgau Danzig – West Prussia, Forster's distrust of the local Nazi leaders led him to deny them political power. Forster filled all the significant positions with his allies from the pre-war Free City of Danzig. This snub created a great bitterness among the local Germans in addition to Forster's Germanisation policies, which denied them a higher status than local Poles.