An excavation in 2015 uncovered a mysterious stone settlement, dating back to the 15th century, next to Dunluce Castle on the coast of Northern Ireland.

Archaeologists stumbled upon the settlement while trying to uncover part of the lost 17th century town of Dunluce near the castle, which once housed the powerful MacQuillan family, Yahoo! News reports.

"This is a tremendously exciting historical development," Mark Durkan, Northern Ireland's environment minister, said in a statement. "Traces of buildings were unearthed close to the cliffs upon which the castle was built. These buildings most likely formed a small settlement, just outside the original castle gate."

Researchers used radiocarbon dating to determine that a fireplace inside a stone structure was used in the late 15th century, the same time the MacQuillans would have lived in the castle.

"We are extremely lucky to make this exciting discovery," Durkan said. "Very few 15th-century buildings, other than those built entirely from stone, have survived in Ulster and normally there would be few traces, if any, for archaeologists to investigate."

"Up to now, we knew there was a substantial 17th century settlement in the fields around Dunluce," he said. "What we are now beginning to uncover are traces of earlier and extensive late medieval settlement activity, which are equally as important as the remains of the 17th century Dunluce Town. This provides an exciting new avenue of research to explore as part of our future investigations at Dunluce."

* Originally published in February 2015.