Abstract
The name of the composer, Kapellmeister and piano virtuoso Johann Joseph Rösler (1771-1812) who was active in Prague and Vienna is often confused for the name of Anton Rössler (Rosetti). Rösler studied philosophy in Prague.
As a self-taught musician, he acquired excellent knowledge in both theory and practice and was offered a place of Kapellmeister at the Guardasoni Opera Company in Prague in 1795. Since 1805, he was active as one of the Kapellmeisters of the opera orchestra of the Burgtheater in Vienna where he also gained recognition as a pianist and composer and he met the Prince Joseph Franz Maximilian Lobkowitz who engaged him as one of his Kapellmeisters.
Rösler has left a handwritten thematic catalogue Repertorio di tutte le mie Composizioni incominciando dall' anno 1796. Considering this list and the found manuscripts Rösler composed 9 operas and 6 cantatas, 2 pantomimes, melodrama, sacred music and more than 100 vocal pieces.
He also wrote symphonies, concertos, chamber music and both original music and transcriptions for keyboard instruments. The first movement of his Piano Concerto in D major (1801) was first wrongly published by Breitkopf&Härtel as a Beethoven's work.
Hans Engel who identified Rösler as the actual author expressed in 1927 his regret about not discovering other two piano concertos of this brilliant composer (Die Entwicklung des deutschen Klavierkonzertes von Mozart bis Liszt. Leipzig: Breitkopf&Härtel, 1927).
Autograph of one of these concertos (Piano Concerto In E flat major, 1801) was identified by the author of this article on the basis of Rösler's list in the Archive of the Prague Conservatoire. The work was published by Bärenreiter Praha in 2018.