n Imperial Circle (Reichskreis, Reichskreise) was a regional grouping of territories of the Holy Roman Empire, primarily for the purpose of organizing a common defense and of collecting imperial taxes, but also as a means of organization within the Reichstag and the Reichskammergericht.
Each circle had a Kreistag (Circle Diet), although not every member of the Kreistag would also be a member of the Reichstag as well.
Initially six circles were created in 1500 as part of the Reichsreform (Imperial Reform):
Originally, the territories held by the Habsburg dynasty and the Electors were not encircled. In 1512, these were organized into four more circles:
These ten circles remained largely unchanged until the early 1790s, when the wars of the French Revolution brought about significant changes to the political map of the Empire.
A number of territories were never encircled: