Castle of Linz  The Castle of Linz () is a castle in Linz am Rhein, Germany, built between 1364 and 1368 by Heinrich von Virneburg, who was the archbishop of Cologne at the time. The main function of the castle was to collect river tolls. During the Neuss War in 1475, the castle was besieged and badly damaged. The castle lost its importance when the town of Linz am Rhein was sold to Prussia in 1820. In 1942–1945, during the Second World War, the castle was used as a prison. The structure today is now privately owned and used as a public venue.