Walter Rubensdörffer in July 1940 as the official service test unit for the then-new Messerschmitt Me 210, the intended successor to the earlier Messerschmitt Bf 110. However, such were the delays in that aircraft’s development that the unit was utilised to develop tactical and strategic practices required to operate the in-service Bf 110s in newer, fighter-bomber and ground-attack roles they were being adapted to. By the time the unit was re-designated I. Gruppe, Schnellkampfgeschwader 210 in April 1941 the unit was based at Abbeville, bombing Allied shipping and land-based targets.