A first castle was built on the island around 1480 and then extended around 1630, but the castle that stands here today was built by Carl Hårleman (1700-1753). He added a fourth floor, two new wings and laid out the park, all in a Rococo style. The interior decor, furniture and the large collection of paintings cover different periods. Adorned with fine original murals, the 14C chapel was modified by Hårleman, who also added the cupola to it.