On 21 July 1943, "Jagdgruppe Süd der ObdL" was formed as a high-altitude fighter unit to combat the RAF's Mosquito twin-engine bomber and reconnaissance aircraft. On 15 August 1943 the unit was redesignated "Jagdgeschwader" 50 and was commanded by "Major" Hermann Graf, the first pilot in history to achieve 200 aerial victories. It was planned to equip JG 50 with the Messerschmitt Me 163 rocket fighter and began training on glider aircraft. Both JG 50 (and its sister unit "Jagdgeschwader" 25) were ultimately unsuccessful in effectively countering the Mosquito and were more successfully used for interception of the US heavy bomber formations during the daylight offensive over Europe in 1943-44. Only one Mosquito was taken down, and even that is subject to dispute.