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 county of Freiburg. The city of Freiburg loaned money from the Habsburgs to purchase their independence in 1366, but they were unable to repay so they defaulted and came under control of the Habsburgs. With the extinction of the Counts of Freiburg in 1457, their remaining territories passed to Baden.
The Breisgau was made part of Further Austria by the Habsburgs, a collection of lands in Swabia and Alsace. The Breisgau was devastated in the Peasant's War of 1525 and the Thirty Years' War (1618 - 1648). In the struggle between France and Austria from the 17th Century onwards, the Breisgau frequently changed hands; the longest occupation was by the French from 1679 until 1697. In 1801 the Austrians ceded the Breisgau to Ercole III of Modena, a relative of the Habsburgs who was displaced from his realm by the French. His successor renamed his state to "Breisgau-Modena" in 1803 but on his death two years later it passed to the and the Württemberg, the latter ceding their portion to the former in 1810.
|on the Adige | Austria (bailiwick) | Breisgau | Brixen | Carinthia | Carniola | Chur | Friuli|
Further Austria | Gorizia | Lower Austria | Styria | Tarasp | Trent | Tyrol | Upper Austria
|Austria (archduchy) | Gradisca | Gurk | Hardegg | Lavant | Losenstein | Rogendorf|
Schaunberg | Seckau | Wolkenstein-Rodenegg