A medieval castle, thought to have been lost for centuries, has been uncovered inside a building on the campus of University College Dublin (UCD). The castle, known as Roebuck Castle, was identified by Professor Tadhg O'Keeffe, a medieval architectural historian at UCD's School of Archaeology. His research, published in Archaeology Ireland magazine, reveals that significant parts of a Norman castle—once a key fortress on one of the main roads into medieval Dublin—remain preserved within the modern building. This discovery adds a layer of historical depth to the university campus, which now may host one of the oldest standing structures in Ireland. The oldest parts of Roebuck Castle date back to the early 13th century, potentially making it the oldest surviving building on an Irish university campus. According to O'Keeffe, medieval features are still intact inside the building, concealed beneath layers of plaster. Rather than tearing it down, the Georgian and Victorian-era builders of the property chose to construct around the existing castle, preserving much of its original structure. Today, the courtyard at the rear of the building is actually the medieval castle's original courtyard. Historical records suggest that Roebuck Castle was built shortly after the Norman invasion of Ireland in 1169. It underwent several modifications during the Middle Ages and was once home to notable figures, including a Lord High Chancellor of Ireland. There is also a tradition that King James II stayed at the castle in 1689 after losing his throne. By the 18th century, the castle had fallen into disrepair and was believed to have been removed during later redevelopment of the site. Clues to the castle's survival were recorded by artist Gabriel Beranger, who visited the ruins around 1765 and painted them in a series of watercolors. These depictions provide valuable insight into the castle's original structure and small architectural details. The discovery of Roebuck Castle is particularly significant because few medieval castles have survived in south Dublin. Many were demolished in the 17th century, with their stones reused in more modern homes. O'Keeffe noted that time has been unkind to these medieval structures, which have left gaps in historical knowledge. He emphasized the importance of this discovery, saying it is wonderful to welcome back Roebuck Castle and ensure it is no longer lost to history.