On September 3, the forces of German 4th Panzer Division under Major General Georg-Hans Reinhardt managed to break through positions of the Polish Łódź Army near Częstochowa and started their march towards the river Vistula and Warsaw. The same day Polish Commander in Chief, Marshal of Poland Edward Rydz-Śmigły ordered the creation of an improvised Command of the Defence of Warsaw (Dowództwo Obrony Warszawy). General Walerian Czuma, the head of the Border Guard (Straż Graniczna), became its commander and Colonel Tadeusz Tomaszewski its Chief of Staff.