The “Fallschirmjäger” were, throughout the war, merged inside fighting systems for the Luftwaffe for an improved coordination with the air forces. The conquest of Crete during operation Merkur, in-may 1941, was one of the biggest successes of German paratroopers. However the casualties had been therefore high that their use was frequently limited to at the very top infantry role above as airborne troops. In March 1944, General Kurt Student's 1st Division Fallschirmjäger, holding their ground among the ruins regarding the Monastery of Montecassino, strenuously resisted the advancing Allies. Their resistance was so intense that they were nicknamed the “Green Devils”.