Once in Britain the division was attached to U.S. XVIII Airborne Corps, under Major General Matthew Ridgway, which commanded all American airborne formations, and which in turn became part of the First Allied Airborne Army when it was formed on 21 August, under the command of Lieutenant General Lewis H. Brereton. Although attached to XVIII Airborne Corps, the division was not chosen to participate in Operation Market Garden, a large-scale airborne operation intended to seize several bridges through the Netherlands to allow the Allied armies to bypass the Rhine river and enter Germany. The 17th was passed over in favour of the 82nd and 101st Airborne Divisions because it had only recently arrived in the European Theater and was considered to be unprepared logistically as it was still collecting its combat equipment. The division was also given command of the 507th Parachute Infantry Regiment. The 507th had fought in Normandy under command of the 82nd Airborne Division and remained in England as a theater reserve during Market Garden. The 507th continued to remain in England as the Allied armies continued their advance towards Germany.