Another cover with special postmarks celebrating the 1200th. anniversary of the Princely Abbey of Corvey. The Princely Abbey of Corvey (German: Fürststift Corvey or Fürstabtei Corvey) is a former Benedictine abbey and ecclesiastical principality now in North Rhine-Westphalia, Germany. It was one of the half-dozen self-ruling princely abbeys of the Holy Roman Empire from the late Middle Ages until 1792 when Corvey was elevated to a prince-bishopric. Corvey, whose territory extended over a vast area, was in turn secularized in 1803 in the course of the German mediatisation and absorbed into the newly created Principality of Nassau-Orange-Fulda. Originally built in 822 and 885 and remodeled in the Baroque period, the abbey is an exceptional example of Carolingian architecture, the oldest surviving example of a westwork, and the oldest standing medieval structure in Westphalia. The original architecture of the abbey, with its vaulted hall and galleries encircling the main room, heavily influenced later western Romanesque and Gothic architecture. The inside of the westwork contains the only known wall paintings of ancient mythology with Christian interpretation in Carolingian times. The former abbey church was listed as a UNESCO World Heritage Site in 2014.