The Principality of Regensburg (Fürstentum Regensburg) enclaved within the Kingdom of Bavaria. The ephemeral principality (1803 to 1810) had been formed with the territories of the former Prince-Bishopric of Regensburg and Free Imperial City of Regensburg. Cropped from a map of the Kingdom of Bavaria published in 1807 by the Geographical Institute of Weimar.