First Allied Airborne Army divisions were initially chosen to take part in Varsity: the British 6th Airborne Division, the US 13th Airborne Division and the US 17th Airborne Division, all of which were assigned to US XVIII Airborne Corps. One of these airborne formations, the British 6th Airborne Division, was a veteran division; it had taken part in Operation Overlord and the assault on Normandy. However, the 17th Airborne Division had only been activated in April 1943 and had arrived in Britain in August 1944, too late to participate in Operation Overlord. The division had also been absent from Operation Market-Garden, and the only
6th Airborne Division advance to the River Seine heavy anti-aircraft artillery regiment used in a field artillery role. In the operation the 6th Airborne Division together with the 7th Armoured Division, the 49th (West Riding) Infantry Division and the 51st (Highland) Infantry Division, formed the I Corps, attached to the First Canadian Army. When issuing his orders, Lieutenant General John Crocker, the Corps commander, aware that the 6th Airborne had almost no artillery, vehicles or engineer equipment, did not expect them to advance quickly. To reach the River Seine the division would have to cross three main rivers, along only two main lines of advance. One route was