The German Order Police (uniformed police) was a key instrument of the security apparatus of Nazi Germany. During the prewar period, SS chief Heinrich Himmler and Kurt Daluege, chief of the Order Police, cooperated in transforming the police force of the Weimar Republic into militarised formations ready to serve the regime's aims of conquest and racial annihilation. Police troops were first formed into battalion-sized formations for the invasion of Poland, where they were deployed for security and policing purposes, also taking part in executions and mass deportations.[1]