Initially the army consisted of two improvised mountain brigades and a number of smaller units, but later in the course of war (on September 6) it was joined by forces of the withdrawing "Armia Kraków", and renamed "Armia Małopolska". From 11 September 1939, it was commanded by General Kazimierz Sosnkowski (after General Fabrycy was reassigned to command the Polish Southern Front). On September 1 in the morning, Karpaty Army was attacked in the area of Czorsztyn by the 4th Light Division of the Wehrmacht, supported by the 2nd Mountain Division. Backed by the Slovakian units (see Slovak invasion of Poland), the German divisions managed to break through Polish positions near Tymbark and Limanowa, causing a gap between Karpaty Army and the retreating Kraków Army. As a result, Polish headquarters agreed for a withdrawal. In the first days of the invasion, Karpaty Army lacked reserve units, as its main forces, the 24th and 11th Infantry Divisions, were either still mobilized, or were on their way towards the area of Tarnów.