BREISGAU, a district of Germany, in the free state of Baden. It extends along the right bank of the Rhine from Basle to Kehl, and includes the principal peaks of the southern Black Forest and the Freiburg valley. The Breisgau, at one time a dis trict or gau (Lat. pages) of the Frankish empire, was ruled dur ing the middle ages by hereditary counts. Of these the earliest recorded is Birtilo (962-995), ancestor of the counts and dukes of Zahringen. On the death of Berchthold V. of Zahringen in 1218, his co-heiresses brought parts of the Breisgau to the counts of Urach and Kyburg, while part went to the margraves of Baden. The male Urach line becoming extinct in 1457, an heiress carried to the house of Baden what had not been alienated to the Habs burgs. In the struggle between France and Austria from the 17th century onwards the Breisgau frequently changed masters. In 1801 Austria was forced to cede it to Ercole III., duke of Modena, in compensation for the duchy of which Napoleon had deprived him. His successor Ferdinand took the title of duke of Modena Breisgau, but on his death in 18o5 the Breisgau was divided be tween Baden and Wurttemberg. The latter ceded its portion to Baden in 181o.
See Stokvis, Manuel d'histoire, etc. (Leyden, .