Geophysical Survey Reveals Lost Castle

Archaeologists conducting a geophysical survey in the grounds of Kasteel Oud Haerlem have discovered the remains of a later previously unknown castle that dates from AD 1250.

Slot Oud Haerlem is a former castle, the remains of which are located on the east side of the North Holland town of Heemskerk in the Netherlands. The original castle was first built in AD 1248 by Simon van Haerlem.

Previous studies in the 1960s had investigated the outer castle earthworks but left the remains in situ with no further investigations. The new geophysical study surveyed an area of 9,000 square metres using a geophysical technique called EMI, Electro Magnetic Induction. The study revealed that the later castle measures 45 by 45 metres square and consists of several rooms.


It was assumed that square castles in the county were built from 1280 under Floris the Fifth, but the new castle discovery suggests that square castles date much earlier and were already being built by his father, William the Second.

The later castle stood for almost 100 years until it was placed under siege for several months and destroyed in 1351 during the Hoekse and Kabeljauwse (the Hook and Cod wars).

The Hook and Cod wars a series of wars and battles in the County of Holland between 1350 and 1490. Most of these wars were fought over the title of count of Holland, but some historians have argued that the underlying reason was because of the power struggle of the bourgeois in the cities against the ruling nobility.

Geophysicist Nancy de Jong told The Mirror: “Stories say that there are mass graves present on the site and that the doomed souls of those who died there were the reason that the castle site was never redeveloped. Right after the destruction of the castle, they cleared most of the remains. What was left was a hilly meadowland for the past 600 years.”


Header Image Credit : Ahaigh9877

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Markus Milligan
Markus Milligan
Markus Milligan - Markus is a journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 7,000 articles across several online publications. Markus is a member of the Association of British Science Writers (ABSW).



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