The handwritten opera scores of the 18th century of the Bavarian State Library, a collection of more than 200 works in over 400 volumes, have been catalogued online, digitized and made available on the Internet for three years starting in February 2017 in a project funded by the German Research Foundation. In the 18th century the Munich electoral court was one of the most important centers of European opera cultivation north of the Alps, alongside Vienna, Berlin, Dresden, Mannheim and Stuttgart. In the first half of the century, in addition to Pietro Torri, whose late Venetian operas dominated Munich for decades, composers such as Bernardo Aliprandi, Giovanni de Porta and Francesco Peli can be mentioned. In 1753 the newly built Residenztheater was opened with Giovanni Ferrandini's 'Catone in Utica'. From that time until 1788, a new opera seria was performed every year to open the carnival season. Until 1767 Andrea Bernasconi, who had been appointed vice-kapellmeister in 1753, composed most of these carnival operas. Thereafter, a different opera composer was commissioned each year to write the opera seria at the electoral court, including Tommaso Traetta, Antonio Sacchini, Pietro Pompeo Sales, Alessio Prati, Antonio Tozzi, Antonio Salieri, Josef Myslivecek and Joseph Willibald Michl. The extensive holdings of handwritten scores directly related to Munich performances were later expanded through additions from bequests and collections and through targeted acquisitions. Digitization and structured online provision provide access to this unique collection for research and music practice.