This was a government agency of the Austro-Hungarian Empire founded in 1894 for the purpose of publishing the series Denkmäler der Tonkunst in Österrieich. The general editor of the series was Guido Adler. From 1894 to 1904, the distributor of the series was the Vienna old firm Artaria, followed with distribution by Breitkopf und Härtel (1905-1913; 1919-1923), Universal Edition (1919-1938). After World War II, the series' distribution was taken over by Akademische Druck- und Verlagsanstalt (1966 to present).
The web site of this project is in German, and is found here.
See Denkmaeler der Tonkunst in Oesterreich