The French in Syria had supported the Iraqi rebellion materially and allowed Luftwaffe aircraft to use their airfields for operations over Iraq. The month-long Syria-Lebanon Campaign in June–July 1941 saw heavy fighting both in the air and on land, until the Vichy French authorities in Syria surrendered on 12 July 1941. In one encounter between the Royal Air Force and the Vichy French Air Force on 15 June 1941, six Gloster Gladiators were jumped by an equal number of Dewoitine D.520 monoplane fighter aircraft.