Formed around a nucleus of pilots already seasoned by their experience as volunteers in the RAF's Eagle Squadrons, the 4th Fighter Group was established in England in October 1942. The 4th was the first group to escort US bombers to Berlin, and participated in the Operation Frantic shuttle missions to Russia. While primarily a bomber escort group, the 4th also played roles in supporting the D-Day landings, Operation Market Garden, the Battle of the Bulge, and the crossing of the Rhine.