It was hoped that the operation would commence during December, and though this proved unrealistic, by the third week of January 1944 a force approaching 600 aircraft had been amassed by stripping five Kampfgruppen (bomber groups) from the Italian front and by rebuilding existing bomber units in the West.[1] On 3 December 1943 Göring issued a directive for Unternehmen Steinbock (Operation Capricorn), with the objective of "avenging terror attacks of the enemy."[36]