The goal of the study is to present certain Händel sources that are unknown or have not yet been researched and to investigate the connection of those sources with the capital city of the Habsburg Monarchy, Vienna. At the center of attention is a performance of a pasticcio of Giulio Cesare in Egitto at the Theater am Kärntnertor in Vienna (Kärntnertortheater) in 1731. The study introduces the printed libretto, which has heretofore been regarded as lost, as well as the score of the work that L. Bennett first brought to light. The rediscovery of the libretto has made possible the comparison of these two sources. Also brought to attention is a copy of a collection of arias from this pasticcio that is held in Bratislava. There is furthermore presentation of certain possibilities regarding the identity of the probable compiler of the pasticcio, the composer Francesco Rinaldi, whose three extant operas premiered in Vienna date from the years 1730–1732. Reference is made in the study to the increased interest in Händel’s works in Vienna around the year 1730, and in connection therewith, reference is also made to a Viennese copy of his opera Admeto, which is kept in Meiningen. The study also asserts that at least one of the scores of Händel’s Agrippina held in the Musiksammlung der Österreichischen Nationalbibliothek had been the property of Count Johann Adam von Questenberg.