Bad Cannstatt, also called Cannstatt (until July 23, 1933) or Kannstadt (until 1900), is one of the outer stadtbezirke, or city boroughs, of Stuttgart in Baden-Württemberg, Germany. Bad Cannstatt is the oldest and most populous of Stuttgart's boroughs, and one of the most historically significant towns in the area of Stuttgart. The town is home to the Cannstatter Wasen and Cannstatter Volksfest beer festivals, the Mercedes-Benz Arena (VfB Stuttgart), the Hanns-Martin-Schleyer-Halle, and the Porsche-Arena. Name Bad Cannstatt's name originates from a Castra stativa, Cannstatt Castrum, the massive Roman Castra that was erected on the hilly ridge in AD 90 to protect the valuable river crossing and local trade. In the past, Bad Cannstatt has been known as simply Cannstatt or Kannstatt, Cannstadt, Canstatt, Kanstatt, and Condistat. Its name was changed to include "Bad" () to mention the town's spas on 23 July 1933. History Bad Cannstatt lies on the Neckar at the convergence of various regional trails. It was founded during the Roman period, although the area was inhabited by the Seelberg mammoth hunters during the last glacial period. Records survive of Roman knowledge of the area's springs. The nearby Sielberg is notable for its caverns and fossils. In 746 Carloman, Mayor of the Palace of Austrasia, called a council at Cannstatt, arrested and executed virtually all nobles of the Alemanni. This marks the transfer of power from the Alemanni to the emerging Carolingians. The present name first appeared as the seat of a court held by Charlemagne in the 8th century while trying the rebellious dukes of Alemannia and Bavaria. Cannstatt was the capital of the county of Württemberg into the 14th or 15th century; the Rotenberg was the location of the ruling house's ancestral castle. Cannstatt subsequently formed part of the duchy, electorate, and kingdom of Württemberg. It lay about from Stuttgart proper, although it has since grown to include Bad Cannstatt. In the 13th or 14th century, Louis the Bavarian expanded its rights and privileges to equality with Esslingen. Its 15th-century cathedral was dedicated to St Uffo. In 1755, the Great Lisbon earthquake caused the town hall to subside about . During the wars which followed the French Revolution, the town was the site on 21 July 1796 of a French victory over the Austrian Empire. In the 19th century, it boasted an attractive town hall, a royal theater, a market house, the Wilhelma and Rosenstein palaces,