At the beginning of the 17th century, King Gustavus Adolphus made plans for a new royal palace. The plans came to naught, but in 1651, his daughter Queen Christina appointed Jean de la Vallée to architect for the royal castles, and among his commissions was to make suggestions for how to improve and update the Tre Kronor Castle. Contemporaneous copperplates from 1654 shows de la Vallée's idea of a more visible castle on a raised plateau with a connecting bridge over the Norrström. Queen Christina remodelled and embellished the existing castle extensively, but no new castle was built during her reign.