In the religiously turbulent times of the late 1600s, it was discovered that illegal Catholic masses were being said at a chapel in the attic of Plas Gunter Mansion. David Lewis and Phillip Evans, two local priests who regularly said mass in the chapel were arrested, tried and executed.
Boarded up for over two hundred years, the hidden chapel and a fine ornate plaster ceiling were uncovered in 1907. The painted altarpiece featuring the Adoration of the Magi and one of the original doors were taken to Abergavenny Museum while the ground floor was divided into retail units.
Today Plas Gunter Mansion is in a poor state of repair. Following a successful appeal, the Welsh Georgian Trust (now Plas Gunter Mansion Trust) bought the building in 2017. In the same year, the Friends of Plas Gunter Mansion was set up and embarked on a campaign to bring Gunter back to life.