"The Vernacular Architecture Group (VAG) is an international organisation dedicated to the study of traditional buildings. Members are typically professional architects, architectural historians or keen enthusiasts.

This year they chose to visit Plas Y Dduallt Manor House in Snowdonia. Literally translated it means 'the hall on the black hillside'. The word black apparently relating to the evil spirits as opposed to the colour of the rock.

Plas y Dduallt is one of the oldest inhabited houses in Wales, dating back to the 15th century. The core of the house is an ancient Welsh hall house which now incorporates the dining room and truss bedroom. It is thought that it was first built as a single storey structure certainly before 1500 and that the suspended floor was installed in about 1550 to create a first floor for sleeping purposes.

In about 1630 the second house at the front was built on as a parlour block with a connecting porch way and passage above. One theory is that the chimneys and floor of the hall house were added at this time.

It was occupied for hundreds of years by the Llwyd family, direct descendants of Llewelyn the Great. Locals call it Cromwell's House as the great man is reputed to have slept here but the more plausible story is that Cromwell's officers were billeted at the house during the siege of Harlech Castle in 1647.

This magnificent house, perched high up above the Vale of Ffestiniog, was more or less derelict in 1962 when Colonel Campbell of the Black Watch bought the property at auction. The Colonel worked closely with the Historic Buildings of Wales, receiving grants and accolades for first class restoration work.

The Colonel was an enthusiastic supporter of the Ffestiniog Railway Company and put his explosives know-how into good use for blasting the rocks to re-open the line up to Blaenau Ffestiniog. In return for his support the Colonel had his own private platform and siding, called Campbell's Platform, which was used by the VAG to travel up the line by steam train to visit this spectacular location.

On arrival at the house the visitors split up into ad hoc groups. Many of them were equipped with torches to explore the darkest crevices of the house. There were numerous heated debates about the length of the crucks in the oak truss bedroom, the age of the oak beams and the variety of religious symbols found in the house warding off evil spirits.

Indeed the records show that there was a shadow of inherited insanity in the Llwyd family; in that the family was 'bewitched' at an earlier time with one child in every generation thereafter being mad and general adversity being suffered. Some were so severely afflicted that they were not fit to mix in society unless accompanied by a more rational person.

The family lived at Dduallt until the late 19th century when according to a local chronicler 'due to the habit the Welsh had of excessive litigation the family fell upon hard times'.

Many of the group were so impressed they vowed to return to explore at their leisure this intriguing house."