The virtuosity of these roles is perhaps attributable to the fact that when he took up the task of composing the opera, Mozart already knew the outstanding reputations of the singers for whom he was writing, and he tailored the arias to their strengths. The first Osmin was Ludwig Fischer, a bass noted for his wide range and skill in leaping over large intervals with ease. Similarly, Mozart wrote of the first Konstanze, Caterina Cavalieri, "I have sacrificed Konstanze's aria a little to the flexible throat of Mlle. Cavalieri."