Oud Haerlem Castle: A Medieval Fortress near Heemskerk
Site at a Glance
- Rating
- 4.5
- Popularity
- Very Low
- Country
- Netherlands
- Primary era
- Medieval
- External website
- Open
- Eras represented
- Medieval
- Civilizations
- Unclassified
- Site type
- Military
- Remains
- Castle
On this page11 sections
History
Oud Haerlem Castle was a medieval fortress in the Netherlands near Heemskerk, built in the mid-thirteenth century by the knight Simon van Haerlem. It formed part of a group of castles associated with William II, Count of Holland, and stood in a strategically important landscape between northern and southern Holland.
Foundation and early lords
In 1248, Simon van Haerlem and his brother-in-law, the knight Wouter van Egmond, acquired the fief of Hofland, a landed estate held from a superior lord in return for service or allegiance. Simon moved from Haarlem to Heemskerk, became the first local lord with administrative and judicial authority there, and is identified as the builder of the castle. At the time, it was called Het huys tot Heemskerck, meaning the house at Heemskerk.
Simon gave the plot of his former house in Haarlem to the Carmelites, a Catholic religious order that began as a community of hermits on Mount Carmel. A convent was later founded on the site. Simon died in 1280 and was succeeded by his son Willem. Willem’s nephew, Jan van Bergen, inherited the castle after him and held it until his death in 1321, when the property reverted to the counts of Holland.
The Polanen lordship
In 1327, the castle was sold to John I, Lord of Polanen, on the condition that it remain an open house for the count. The transaction was probably influenced by Willem van Duvenvoorde, John’s half-brother, who was a financier and favored court figure under successive counts of Holland. John II, Lord of Polanen, later held the castle together with high jurisdiction after receiving it from Margaret II, Countess of Hainaut.
The concentration of castles near Heemskerk has been associated with the medieval geography of the IJ and Wijkermeer. The waterway left a narrow strip of land connecting northern and southern Holland, and the counts of Holland may have used castles in this zone as a defensive line against invasions from West Friesland.
Destruction in the Hook and Cod Wars
Willem van Duvenvoorde and the Polanen family belonged to the Hook faction during the Hook and Cod Wars, a series of conflicts over political power in the County of Holland and neighboring territories. After William V of Holland, also known as William of Bavaria, returned to Holland in February 1351, he launched a campaign against castles held by his opponents.
Oud Haerlem resisted for an estimated period of up to eleven months before falling in an assault. The attackers used siege engines, including one or more trebuchets, medieval machines designed to throw large projectiles against fortifications. The castle was demolished in 1351 while John II of Polanen owned it, although he was not present during the siege.
By 1379, the site was described as the ground where the castle had stood. A description from 1551 still referred to its inner and outer baileys, double moats, and channels. The ruins were repeatedly quarried for stone, leading their owners to protest and seek payment. In 1866, a large part of the site was quarried for material used in the restoration of Brederode Castle.
Rediscovery and archaeological investigation
Aerial photography in the 1930s led to the castle’s rediscovery. Archaeologist Jaap Renaud made a brief investigation in 1943, followed by more extensive but incomplete excavations from 1960 to 1962. His work relied mainly on trenches, and the excavated area was long interpreted as the main castle.
Renaud’s excavation was never fully published, and an effort to develop his findings in the 1980s did not succeed. After important material from his research emerged from a private archive following his death in 2007, Jean Roefstra and E.H.P. Cordfunke began a new examination in 2010. Their study corrected the orientation of Renaud’s published map and established that a small moat had surrounded the central elevation before being filled during the thirteenth century.
Non-invasive investigations carried out between 2019 and 2021 used ground-penetrating radar, magnetometry, electromagnetic induction, geopositioning, and elevation data. These methods detect buried structures and materials without excavation. The surveys revealed a previously unrecognized square structure measuring 45 by 45 metres. It was first interpreted in 2020 as the outer bailey that Renaud had not located, but the 2021 interpretation identified it as the main castle. This conclusion remains compatible with the possibility that the castle developed from an earlier tower house in the area excavated by Renaud.
A major medieval bronze hoard was found by Renaud during the early 1960s. Concerned that the discovery might encourage looting, he did not reveal its precise location. The information was recovered from a private archive after his death. In the 1990s, proposed redevelopment that included a golf course was halted after Renaud personally intervened, despite municipal approval of the plans. The archaeological remains were placed on the list of protected national archaeological monuments in 1977.
Remains
The castle complex covers approximately 9,000 square metres on the eastern edge of modern Heemskerk, about 400 metres south of Assumburg Castle. Its surviving layout includes a large square main castle, an outer bailey, a voorhof or outer enclosure, several layers of moats, and associated buildings. Much of the complex survives underground in good condition, while above-ground traces appear mainly as irregular elevations in a meadow, with structural remains exposed at the surface in some places.
Main castle
The main castle was a very large square structure measuring at least 45 by 45 metres. It probably had round towers at its four corners, although the complete arrangement of towers remains uncertain. Several wings or buildings occupied the interior, apparently along all four walls. Pottery recovered during work in 2000 and 2001 places its construction around 1250, before the reign of Floris V, Count of Holland, who ruled from 1266 to 1296. The main structure therefore may be the earliest known square castle in Holland built before 1280. It stood for about a century before its destruction in 1351.
Earlier tower house and outer bailey
A central elevation contains substantial debris and was once reconstructed as the site of a donjon, the principal fortified tower of a medieval castle. Later interpretation places an earlier tower house or donjon here, probably built by Simon van Haerlem. A small moat surrounded this central elevation before it was filled, after which an enclosing defensive wall was constructed. The southeast tower contained an entrance, while a small square tower in the north wall provided access to the outer bailey.
The outer bailey formed an almost rectangular enclosure with a projecting tower at its southeast corner. A structure about 7 by 10 metres stood in its northwestern quarter and was probably a building. Renaud identified two round towers at the western corners, a possible square gate tower in the middle of the northern side, and a projecting square tower on the southeast side. The central elevation contains the remains of substantial building debris.
Voorhof and associated buildings
The voorhof surrounded the entire main castle and about half of the outer bailey. Unlike a fortified bailey, this outer enclosure could be protected by water or a simpler boundary. Three probable buildings stood in its northern part, including one measuring about 30 by 17 metres. A round structure at the southeast corner may have been a defensive tower or a windmill mounted on a tower. A bridge extended outward from the middle of the southern side. The 2021 interpretation also identified houses and stables within the enclosure, together with a probable tithe barn, a building for storing agricultural dues paid in kind.
Moats and defensive perimeter
The complex had an unusually extensive defensive perimeter. An approximately figure-eight-shaped moat surrounded the main castle and outer bailey, while its western section formed part of a larger moat enclosing the main castle, the outer bailey, and the voorhof. A narrow strip of land outside this moat was surrounded by a second complete moat, and the same pattern continued on at least the south, west, and east sides. Reaching the main castle required crossing between three and five moats. Parts of this arrangement remain visible in the landscape.
Bronze hoard
The hoard recovered at the site consists of 15 large, finely made medieval bronze objects. It is described as the largest medieval bronze hoard discovered in the Netherlands and provides an important group of movable evidence associated with the castle.
Surveys conducted in May and June 2020 mapped the castle’s contours and foundations without disturbing the ground. Together with the excavations and later reexamination of Renaud’s material, these investigations have reshaped the understanding of the site’s organization and identified the buried main castle within a complex of enclosures, buildings, and water defenses.
