Franz Xaver Gerl low vocal range; Branscombe (1991) observes that the very low notes that Mozart included in the part of Sarastro have been "the despair of many a bass singer since." By 1787 he had joined the theatrical company of Emanuel Schikaneder, for which he sang the demanding role of Osmin in Mozart's opera "The Abduction from the Seraglio" and other roles. In 1789 the troupe settled at the Theater auf der Wieden in Vienna. Gerl participated in a system of joint composition used by Schikaneder's troupe, in which "Singspiele" were produced rapidly by having several composers collaborate. As such, Gerl may
Persian Letters texts and renewed perspectives. Particularly important were the extensively annotated edition by Paul Vernière and the research of Robert Shackleton on Muslim chronology; also studies by Roger Laufer, Pauline Kra and Roger Mercier, which put new focus on the work’s unity and integrated the seraglio into its overall meaning. Others who have followed have looked into the ramifications of epistolary form, the structure and meaning of the seraglio, Usbek’s contradictions. Beginning about 1970 it is religion (Kra) and especially politics (Ehrard, Goulemot, Benrekassa) which predominate in studies on "Lettres persanes", with a progressive return to the role of the seraglio