This is the inner courtyard of the Kaiserburg (Emperor's Castle). For its first 500 years this castle was the residence of all Germany's kings and emperors, and hosted virtually all important leaders and royalty of the time. While German emperors never had an actual capitol or home base as such, Nuremberg came as close to this distinction as possible. It is one of the very few castles to have had the official privilege of housing the imperial regalia and bear the symbol of the empire on its walls.
inner courtyard