The Central Army Group (CENTAG) was a NATO military formation comprising four Army Corps from two NATO member nations. During the Cold War CENTAG was NATO's forward defence in the Southern half of the Federal Republic of Germany (FRG). The NORTHERN half of the Federal Republic of Germany was defended by the four Army Corps of NATO's Northern Army Group (NORTHAG). During war time CENTAG would command four frontline corps (II German, III German, V US, VII US). Air support was provided by Fourth Allied Tactical Air Force.