[1] Established around 1170, the moated castle was originally square-shaped with corner towers connected by a curtain wall.
Under King Christian IV, [4] additional work was performed by the Italian architect Domenicus Badiaz in 1607, when the main tower (Knudstårnet) received a spire similar to that of Copenhagen's Blåtårn.
Nevertheless, encouraged by local interest in the building, the National Museum of Denmark decided to undertake extensive restoration work under the leadership of Mogens Clemmensen.
In general, Clemmensen based his work on the state of the castle under Christian III but he also added numerous details he discovered in other sources, not always clearly documenting them.
The museum had three primary operations: Nyborg Slot including Borgmestergården, Johannes Larsen Museet and the Vikingmuseum Ladby.