Historically, the place was founded by the Spanheim Duke Herman as a stronghold sited across the commercial routes in the area. Its first mention dates from the late 12th century in a document in which Duke Ulric II. exempted St. Paul's Abbey from the toll charge "in "foro Chlagenvurth"". That settlement occupied an area that was subject to frequent flooding, so in 1246 Duke Herman's son, Duke Bernhard von Spanheim, moved it to a safer position and is thus considered to be the actual founder of the market place, which in 1252 received a city charter.