'Lost' medieval castle found hiding in plain sight after professor spots telltale clues

The discovery was announced by University College Dublin (UCD), in Dublin, Ireland, on Sept. 18.

The school announced in a release - entitled "'Lost' medieval castle found hiding inside UCD building" - that medieval archaeology professor Tadhg O'Keeffe found substantial portions of the medieval Roebuck Castle still survive within the university's present-day building.

The present-day Roebuck Castle retained the name of its medieval predecessor - but the Victorian-looking building was long believed to contain little, if any, of the original castle.

The original structure had fallen into ruin by the 18th century and was later incorporated into a residence that underwent extensive alterations, including a major Victorian makeover in 1874. UCD purchased the property in 1986.

"I would say that 70 to 80% of the building is still there, hidden under Victorian plaster," he said.

"I wasn't terribly optimistic," O'Keeffe said. "When I got into the building and had a look around, I realized that actually, most of the castle is still there, inside the building.

"It's not obvious to the naked eye," he continued. "It's not obvious to a non-expert. But I specialize in medieval castle architecture, and I saw all the indications when I went in that the castle is still there."

The clues were hiding beneath the building's more modern appearance.

O'Keeffe pointed to unusually thick walls, along with a stone vault and arched stone roof, as evidence of the building's medieval past.

"The gate tower is very clear on the inside," he said.

"Everything is plastered over so you can't see the original stonework anymore, but it's all clearly still there," he said. "Also, the windows are splayed, and splayed windows are a real indication of a medieval date."

Roebuck Castle also stands out for another reason: Researchers know who owned it through much of the Middle Ages.

The owners were "people of some significance," O'Keeffe added.

"Another resident at one stage, temporarily, was King James II. It's reputed that he lived there briefly in the late 1600s."

That level of detail is unusual, O'Keeffe said, because records for castles around Dublin are generally sparse.

Although the renovations preserved much of the medieval castle, O'Keeffe said, it appears to have been more a matter of practicality than historic preservation.

"There was no policy of preservation. There was not a particular interest in the medieval building," he said.

"They clearly figured that the fastest way to do that was to simply leave those walls and incorporate them."

O'Keeffe said the discovery suggests other castles in Ireland that are presumed lost could still survive within later buildings.

"The great takeaway ... is never assume things are gone," he said. "You have to go in and look. You have to explore."