A Vast Viking Massacre May Have Spilt Blood In This Irish Cave

Hundreds of human bones have been found in Dunmore Cave, including those of children and babies.


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

The grassy entrance to the Dunmore Caves in Ireland where a Viking Massacre may have took place.

The steps into Dunmore Cave lead to a fascinating archaeological site that still leaves questions. Image credit: Mark Heard/Flickr (CC BY-NC 2.0)

Something very strange went down in Dunmore Cave. Located in a quiet patch of Ireland, it’s said this cavern is filled with hundreds of human bones, along with dozens of silver and bronze items. Its story is still not fully explained, but some suspect that this was the sight of a Viking massacre over a thousand years ago.

Dunmore Cave can be found in Ballyfoyle, just a short drive from the city of Kilkenny. The cavern features numerous chambers and burrows some 310 meters (1,030 feet) into the surrounding limestone geology. 


The Annals of the Four Masters, which chronicles thousands of years of Irish history up until 1616 CE, explains that the Derc Ferna, which might be an earlier name for Dunmore Cave, was the site of a Viking massacre in 930 CE. 

However, the story behind the victims has been up for debate over the years.

One of the earliest reports comes from bishop George Berkeley who visited the cave in the early 1700s as a boy and remembered hearing tales of bones stacked up in the cavern’s murky depths. 

“Tis likewise reported that there are great heaps of dead men's bones to be seen piled up in the remote recesses of this cavern,” reads one of his accounts.


Marauding Viking invaders from Denmark is often the prime explanation, but there has also been speculation they may have been soldiers from Ireland’s Eleven Years War (1641 to 1653) or victims of the Irish Rebellion of 1798. 

Centuries later, archaeologists in 2007 managed to document at least 351 human bones in Dunmore Cave that belonged to over a dozen different people, including many women, children, and even infants. 

Importantly, a study in 2004/2005 managed to radiocarbon date the bones. This ruled out the possibility of the bones belonging to 1798 rebels or victims of the Eleven Years War, and indicated that many of the remains date to around the 10th century CE, which neatly matches up with accounts of a Viking massacre in 930 CE.

Likewise, a number of Viking silver coins, dated to around 930 CE, have been discovered at the cave, as well as a collection of jewelry and beads. 


It’s well known that the 10th century was the prime time for Viking raids. Norseman from Scandinavia would use their seafaring skills to travel to Britain, Ireland, and mainland Europe where they would pillage Christian lands for money and resources. As shown by the archaeological record, these could often be bloody conflicts. 

One hypothesis of the Dunmore Cave bones is that the local people hid in the cave when news of Viking invaders came, hence why there are so many children and women found among the remains. The Vikings lit fires at the entrance of the cave, hoping to smoke out the fleeing townsfolk and capture them to sell on the slave market. This would also account for the discovery of charred remains and rock in the cavern. The cave eventually filled with smoke and oxygen was depleted, killing all of the desperate people who took shelter here.

Still, however, many questions remain. While the cave has a crystal clear link to the Vikings, there is still a chance that the cave’s remains are not evidence of mass slaughter, but simply a Viking burial ground similar to those found elsewhere in Ireland. 

“Is Dunmore Cave burial place or is it the site of the tragic massacre recorded in the annals? Do the human remains reflect Viking burials on 'pagan' ground or do they represent innocent victims of a Viking massacre? Only further research and excavations will illuminate these key questions,” concludes the 2007 report on the cave. 

  • tag
  • history,

  • Ireland,

  • viking,

  • massacre,

  • human remains,

  • Archaelogy,

  • medieval history,

  • viking age