This article does not cite any sources. (December 2009) (Learn how and when to remove this template message)
The Fricktal ("Frick Valley") region is the northwest extension of the Swiss canton of Aargau. It is situated in Northwestern Switzerland east of Basel, between the High Rhine forming the border with Germany in the north and the Jura Mountains in the south. The Fricktal contains the districts of Laufenburg and Rheinfelden. The region takes its name from its former chief village Frick.
In the Early Middle Ages, Fricktal formed part of the Alamannian Augstgau shire between the Rhine and Aar rivers, from the 10th century onwards of the smaller Frickgau region within Upper Burgundy. The western Fricktal was held by the Burgundian Lords of Rheinfelden, their last scion Rudolf of Rheinfelden became Duke of Swabia in 1057 and upon his death in 1080 his possessions passed to his son in law Berthold II from the House of Zähringen. After the extinction of the line in 1218, the area eventually passed to the Counts of Habsburg, who already held the Vogtei of Laufenburg.
After the Habsburg dynasty had lost large parts of its original Swabian possessions south of the Rhine to the Swiss Confederacy at the 1386 Battle of Sempach, the remaining Fricktal was administered from the Oberamt Breisgau of Further Austria (Vorderösterreich) at Freiburg, while the adjacent Unteraargau region to the south was finally conquered by the Swiss at Bern in 1415. In 1469 the indebted Archduke Sigismund of Further Austria sold the Breisgau with Fricktal to the Burgundian Duke Charles the Bold, nevertheless upon Charles' death in 1477 it reverted to Archduke Maximilian I of Habsburg by marriage with the duke's daughter Mary the Rich.
In the early 18th century, the citizens of Bern attempted to purchase Fricktal from the Habsburg Emperors without success. Subsequent to the 1797 Treaty of Campo Formio, France occupied Fricktal, and in 1802 it was briefly a canton of the Helvetic Republic, as the Canton of Fricktal. On 9 March 1803, Fricktal was integrated into the Aargau canton of the Swiss Confederation by order of Napoleon.