on viola. Mergentheim retained this role until the dissolution of the order in the countries of the Rheinbund in 1809 by Napoleon. Mergentheim's fortunes declined after that but were reversed in 1826, when a shepherd by the name of Franz Gehring discovered rich mineral springs in the surrounding area, during the time when spas were expanding in Germany at a rapid pace. The water turned out to be the strongest sodium-sulfate water in Europe, reportedly effective for the treatment of digestive disorders. In the 1970s during the Gemeindereform (administrative reform) several neighbouring villages were incorporated into the municipality. Arts and culture Attractions Mergentheim Palace The best-known sight of Bad Mergentheim is the Deutschordensschloss, the castle where the Teutonic Knights once had their home base. It is a complex of buildings built over a period of eight hundred years. The first buildings of the castle were probably erected as early as the 12th century. The castle was expanded in the late 16th century under Grand Master Walther von Cronberg. Over the course of time a representative Renaissance complex was built by connecting the individual buildings in the inner palace courtyard to a closed ring of buildings. In 1574, the main architect, , also constructed the spiral staircase between the west and north wing. Today the castle houses the Deutschordensmuseum (museum of the Teutonic Order). The English landscape garden between palace and spa building is mainly due to Archduke Maximilian Franz. In 1797, he had a "mosque" built there to recall the past Turkish threat and in 1802 the Schellenhäusle, a late Chinoiserie. The obelisk was built under Duke Paul von Württemberg, a memorial for a dog that saved his life on one of his expeditions. The castle complex is dominated by the Schlosskirche (palace church), begun in 1730 under Franz Ludwig Herzog von Pfalz-Neuburg in Baroque style. It was finished in 1735 under Clemens August von Wittelsbach. The plans for the interior were drawn up by François de Cuvilliés, the Electoral court architect of Cologne. Architects working on site were Joseph Roth and Friedrich Kirchenmayer. Its Rococo interior features elaborate ceiling frescos by the court painter , depicting The Defense of Faith, the Glorification of the Cross in Heaven and on Earth and the Emperor Constantine's Vision of the Cross. The main altar painting is Die Salbung Jesu durch Maria in Bethanien by local painter . Side altar paintings were by