As the conquest of the Aargau was the first made by the Confederates, their delegates (or the federal diet) naturally met at Baden, from 1426 to about 1712, to settle matters relating to these subject lands, so that during that period Baden was really the capital of Switzerland.
Baden was the capital of the canton of Baden, from 1798 to 1803, when the canton of Aargau was created.
In 1798 the Bernese bit became the canton of Aargau of the Helvetic Republic, the remainder forming the canton of Baden.