Altenburg, Lower Austria, municipality in the district of Horn, alt. 388 m, pop. 737, area 28.12 km2, above the Kamptal Valley southwest of Horn - Institut fuer Oeko-Ethologie (Institute for Eco-Ethology); mostly excursion tourism. - The town is dominated by the Benedictine monastery founded in 1144 by Count von Poigen-Rebgau. Parts of Medieval buildings have been excavated; the originally Romanesque collegiate church was changed to the Gothic style in 1265, then renovated in the Baroque style in 1730/1733 by J. Munggenast. The frescoes were painted by P. Troger in 1732/1733, the altarpieces by P. Troger (1734) and J. G. Schmidt (1735). The most notable parts of the monastery building are the Kaiserstiege staircase (with fresco by P. Troger), the Marmortrakt (marble wing), also known as Kaisertrakt (emperor's wing), with 6 halls, the library with its frescoes by Troger, as well as the crypt below with its grotesque danse macabre frescoes. The monastery was closed 1940-1947, severely damaged during the war and post-war period (Soviet occupation) and gradually renovated thereafter (completed in 1962). Several cultural events are held in Altenburg in the summer (Altenburger Saengerknaben, Summer Theatre, Chamber Music Festival).
Further reading#Festschrift 850 Jahre Altenburg, 1994; B. Reichenauer, P. Troger in der Stiftskirche Altenburg, 1997.