Originally Gothic in style, founded in the early 15th century to be a seat of the Mazovian Dukes, The Royal Castle extension works started in 1568 on the initiative of King Sigismund Augustus; its considerable remodelling took place during the reign of King Sigismund III, who transferred the capital of Poland from Cracow to Warsaw. In the years 1765-1794 a sequence of chambers and rooms were prepared and furnished in the eastern wing according to a design by Dominik Merlini and Jan Christian Kamsetzwer. The Royal Castle also hosts exhibitions from European galleries.