Twenty “presumably medieval” skeletons were discovered in a mass burial in Vianen by municipal employees excavating a moat. It is believed that the preponderance of the remains are those of males aged 15 to 30 who lived between the late Middle Ages and the 18th century.

A number of rusty nails were also collected from the scene, which suggests the stacked skeletons were initially buried in a wooden box. The rare discovery lies just outside the grounds of Batestein Castle, leading archaeologists to believe there may be more skeletons hiding in the area.

The remains were discovered last week on Friday, with nine skeletons confirmed by the evening. However, archaeologists returned to the gruesome excavation site Monday to find 11 more – bringing the total to 20.

Alderwoman Christa Hendriksen, one of the archaeologists, expressed “astonishment” at both the discovery and the fact that the corpses were heaped.

The lack of artifacts, such as buttons or jewelry, among the remains suggests that this may have been a mass homicide, as the team anticipated to discover items such as buttons or jewelry.

It also raises speculation that the skeletons were found outside of Batestein Castle. The structure was built in the 14th century and was plagued by hardship.

In 1567, the surrounding town and castle was overrun by the Spanish Army. More than a century later, fireworks sparked a large fire inside the castle’s walls and due to financial problems, it was never rebuilt.

The large keep was torn down in 1771, the rest of the castle followed in 1828 through 1829. The only thing left at present of the castle are part of the decorative gate, called the Hof or Bosch Gate, and some connecting wall parts. The former castle terrain is now built over with houses.