The Breisgau is a region of far southwestern Baden-Württemberg, Germany, located around Freiburg between the River Rhine and the foothills of the Black Forest. The Breisgau was originally known as the "Breisachgau" (i.e.; the country around Breisach) and was created in the reorganisation of the Frankish Empire by Charlemagne. The first counts of the Breisgau were the ancestors of the powerful House of Zähringen, of which the county would remain a principal land. After the death of Berthold V, his co-heiresses brought parts of the county to Urach and Kyburg, while the remaining portion passed to Baden, a younger line of the Dukes of Zähringen. In 1273 the Kyburg portion passed to the House of Habsburg by marriage. The Counts of Urach partitioned in 1236, with their portion forming the new c