The Venetian castle is inhabited, ever since it has been built. There are still descendants of the first French and Venetian nobles who arrived on the island of Naxos after the 4th Crusade. According to local tradition, the castle was built by Markos Sanoudos. There are still some of the walls of the famous tower of Sanoudos. The School of the Ursulins was built on top of the ruins after part of the tower collapsed.
Τhe Castle was not communicating with the sea, but with the inland of the island for safety reasons. The gates of the Castle are three: The "Paraporti", the southern gate, which is the main entrance to the Castle, the famous northern entrance known as "Trani Porta", and Piso Paraporti on the southeast side, which is not preserved anymore.
Of the twelve towers that once protecteed the Castle, only one is preserved to date, the tower of Krispi, which serves as a Byzantine Museum. With the conversion of many mansions to museums and the restoration of others by their owners, Naxos Castle is a lively medieval museum with a unique atmosphere.