A Panzer division was one of the armored (tank) divisions in the army of Nazi Germany during World War II. Panzer divisions were the key element of German success in the blitzkrieg operations of the early years of World War II. Later the Waffen-SS formed its own panzer divisions, and even the Luftwaffe fielded an elite panzer division: the Hermann Göring Division. A panzer division was a combined arms formation, having both tanks (, , usually shortened to ""), mechanized and motorized infantry, along with artillery, anti-aircraft and other integrated support elements. At the start of the war, panzer divisions were more effective than the equivalent Allied armored divisions due to their combined arms doctrine, even though they had fewer and generally less technically-advanced tanks. By mid-war, though German tanks had often become technically superior to Allied tanks, Allied armored warfare and combined arms doctrines generally caught up with the Germans, and shortages reduced the combat readiness of panzer divisions. The proportions of the components of panzer divisions changed over time. The World War II German equivalent of a mechanized infantry division is Panzergrenadierdivision ('armored infantry division'). This is similar to a panzer division, but with a higher proportion of infantry and assault guns and fewer tanks. Pre-war development Heinz Guderian first proposed the formation of panzer units larger than a regiment, but the inspector of motorized troops, Otto von Stuelpnagel, rejected the proposal. After his replacement by Oswald Lutz, Guderian's mentor, the idea gained more support in the Wehrmacht, and after 1933 was also supported by Adolf Hitler. The first three panzer divisions were formed on 15 October 1935. The 1st Panzerdivision was formed in Weimar and commanded by Maximilian von Weichs, the 2nd Panzerdivision was formed in Würzburg and commanded by Guderian, and the 3rd Panzerdivision was formed in Berlin and commanded by Ernst Feßmann. Most other armies of the era organized their tanks into "tank brigades" that required additional infantry and artillery support. Panzer divisions had their own organic infantry and artillery support. This led to a change in operational doctrine: instead of the tanks supporting operations by other arms, the tanks led operations, with other arms supporting them. Since the panzer divisions had the supporting arms included, they could operate independently from other units. World War II These first panzer divisions (1st through 5th) were composed of two tank regiments, one motorised infantry regiment of two