The House of Zähringen () was a dynasty of Swabian nobility. The family's name derived from Zähringen Castle near Freiburg im Breisgau. The Zähringer in the 12th century used the title of Duke of Zähringen, in compensation for having conceded the title of Duke of Swabia to the Staufer in 1098. The Zähringer were granted the special title of Rector of Burgundy in 1127, and they continued to use both titles until the extinction of the ducal line in 1218. The territories and fiefs held by the Zähringer were known as the 'Duchy of Zähringen' (), but it was not seen as a duchy in equal standing with the old stem duchies. The Zähringer attempted to expand their territories in Swabia and Burgundy into a fully recognized duchy, but their expansion was halted in the 1130s due to their feud with the Welfs. Pursuing their territorial ambitions, the Zähringer founded numerous cities and monasteries on either side of the Black Forest, as well as in the western Swiss Plateau. After the extinction of the ducal line in 1218, parts of the family's territories reverted to the crown (attained imperial immediacy), while other parts were divided between the houses of Kyburg, Urach and Fürstenberg. History The earliest-known ancestor of the family was one Berthold, Count in the Breisgau (d. 982), who was first mentioned in 962. In view of his name, he may have been related to the Alemannic Ahalolfing dynasty. Count Berthold's great-grandson, the later Berthold II, Duke of Carinthia (posthumously known as Berthold I of Zähringen, c. 1000–1078), held several lordships (Herrschaften) in the Breisgau, in Thurgau, Ortenau and Baar. By his mother, he was related to the rising Hohenstaufen family. Emperor Henry III had promised his vassal Berthold the Duchy of Swabia, but this was not fulfilled, as upon Henry's death, his widow Agnes of Poitou appointed Count Rudolf of Rheinfelden to the position of Duke of Swabia in 1057. In compensation, Berthold was made Duke of Carinthia and Margrave of Verona in 1061. However, this dignity was only a titular one, and Berthold subsequently lost it when, in the course of the Investiture Controversy, he joined the rising of his former rival Rudolf of Rheinfelden against German king Henry IV in 1073. Berthold's son Berthold II (c. 1050–1111), who like his father fought against Henry IV, inherited a lot of the lands of Rudolf's son Count Berthold