At the end of the 13th century, Florens V, count of Holland built at least five strongholds in the northern region of Noord-Holland, in the Netherlands. Apart from controlling the supply roads he also built them to consolidate his ultimate victory over the Westfrisians.
He started building the castles at Wijdenes and in Medemblik (the present Radboud Castle). After that, somewhat north of the city of Alkmaar he built Nieuwburg Castle (Nijenburg Castle) and Middelburg Castle. To defend the dam in the former river Rekere (at the present village of Krabbendam), he built Nuwendoorn Castle (Nieuwendoorn Castle).
If there ever was a castle on a mound at the village of Eenigenburg, as a minor twin of Nuwendoorn Castle, is rather doubtful.
Of all castles mentioned here, just one is still standing: Radboud Castle; all others have completely vanished or some remains of the foundations are left.
Radboud Castle has the function of a museum-castle now. The consolidated foundations of Nuwendoorn Castle are also worth to visiting.
The 'Zes Wielen'-region at Alkmaar/Oudorp has been declared to be a cultural heritage. There you will find the silhouette of the Nieuwburg-foundations, which were made visible by raising them by means of an earthen embankment.
Torenburg Castle was an older castle. It was built (or rebuilt) by Florens' father, William II of Holland in about AD 1250, just outside the city-boundary of Alkmaar. This castle also played a role during the struggle of the counts of Holland suppressing the Westfrisians. The foundations of this castle have vanished for ever, after being removed during the digging of the Noord-Hollands Kanaal. Some street names ('Torenburg', 'Kooltuin', 'Dijk' en 'Koningsweg') in the city of Alkmaar are a reminiscence of this castle.
The Countship of Holland was a property of Albrecht (Albert) of Bavaria from 1358 to 1404. By his order, Schagen Castle was built at the end of the 14th century. In the first place as a residence of the Lord of Schagen, but in AD 1440 it was rebuilt as a real castle by one of his bastard-sons, William 'the Bastard' of Holland. At present, just two towers of this late Medieval castle have remained. In 2001 the castle has been reconstructed, according contemporary rules of architecture and structure.
Two other Westfrisian castles of late-medieval date, are subject of investigation and discussion. The remains are probably discovered. These castles are: Hoogwoud Castle and Berkhout Castle in De Goorn.