Giuseppe Sarti's opera Fra i due litiganti, premiered in Milan in 1782, was the first great success of the reconstituted Italian opera company in Vienna in 1783. The opera sustained its enormous Viennese popularity for years, while also being performed in over one hundred other European cities by 1800. Mozart's quotation of the work in Don Giovanni testifies to its continuing appeal. But the version of the opera that was so successful in many parts of Europe differed substantially from the Milanese original. The surviving manuscript scores and printed librettos reveal that a standardized Viennese version of Fra i due litiganti, in which more than a third of the original arias were replaced, became the basis for productions across much of Europe. This unexpected standardization may reflect the prestige of Vienna and its role as a distribution point for opera scores, especially since many of the manuscripts were produced by Wenzel Sukowaty, the copyist for the Viennese court theaters. The Viennese changes surprisingly include arias for Nancy Storace and Francesco Benucci—later Mozart's Susanna and Figaro—who had themselves created the same roles in Milan. (Normally arias would be substituted to suit the preferences of new singers.) These alterations not only changed the profiles of the characters, but allowed Storace and Benucci to define themselves for the Viennese public, establishing the musical and dramatic personae that quickly made them the beloved favorites of Viennese audiences.