A Council of State had the initial fortress (14C) built but the current castle was built by Gustav Vasa. The national portrait collection (4 000 works dating from the 16C to 21C) is housed over three stages. The second floor is the main floor: its decor dates mainly from 1770-1780. The largest room among the royal apartments is the council hall (Rikssalen). In the tower of the theatre, the "round salon" (Runda salongen) is typically Gustavian. There is also an elegant theatre and its machinery, a neo-Classical masterpiece by Erik Palmstedt (1741-1803).