Henry the Lion had this castle built in around 1175 as a residence inspired by the imperial palaces of the time. It was completely rebuilt following many alterations and fire damage from 1887 to 1906 in a historicized manner. The castle now accommodates the mediaeval section of Herzog Anton Ulrich Museum: In the „Knappensaal“ hall, some of the Guelph treasures are on display as well as valuable liturgicalclothing and the original Braunschweig Lion. On the upper floor there is a splendid great hall.