Zähringen is the name of an old German noble family in Swabia, who founded a large number of cities in what are today Switzerland and the German state of Baden-Württemberg. The name is derived from Zähringen castle near Freiburg im Breisgau, now in ruins, which the dukes founded in 1120. While the junior line who first assumed the title 'Duke of Zähringen', a cadet branch of the House of Baden, became extinct in 1218, the senior line persists and currently uses the title 'Margrave of Baden, Duke of Zähringen'.