I am a regular visitor the grounds of Erddig house and I blogged previously about its fabulous ironwork gates. Today, in cold weather, I parked at the NT car park and walked along muddy paths through woodland to visit Erddig Castle.
Relying on Helen Burnham’s guidebook ‘Clwyd and Powys’ and the online HER ‘Archwilio’, there is only basic information known about this impressive earth and timber castle of presumed 12th-century date. It may relate to the medieval documentary references to the castle of ‘Bromfield’. However, this monument’s history is primarily from its unexcavated surviving earthworks.
The castle is situated on a promontary above the Clywedog on its eastern side and the Black Brook on its west and north. The fortifications thus utilised steep natural slopes on all but its southern approach. A further dimension to its location is the pre-existing, ninth-century linear earthwork Wat’s Dyke which entered the castle on the west side and was clearly utilised as part of its defences.
The bailey is large and rectangular space created by enhanced pre-existing slopes on its west and east and cutting across the promontary to the north and south. The southern bailey ditch has to be seen to be believed – it is a massive 6m deep, with a notable kink in its direction where a drawbridge might have once been situated.
The northern ditch is big too, at c. 4.5m deep, and marks the bailey from the impressive motte, 21.5m in diameter with a c. 10m platform on top, situated at the head of the promontary. As Burnham notes, the arrangement is reminiscent of an Iron Age promontary fort and it remains possible that the castle remodelled and, in the processed, enlarged and conceals a far earlier set of fortifications.
Appreciating the enormity of this monument today is a challenge given the heavy woodland – part of an 18th-century landscape park. Despite the absence of any discernible earthworks within the bailey, and the views obscured by trees, this is clearly a dramatically located and fascinating ancient monument best visited in wintertime. While its location is clearly dictated by defensive motivations, it is not implausible to spectaculate that it was also situated at or close to a pre-Norman central place, located on Wat’s Dyke and controlling the Clywedog valley below.
I usually discuss the heritage interpretation of sites I visit. In this case, there is nothing to talk about. The site has no signposts and no display board; simply a metal frame where a sign might have once existed…
Archaeo𝔡𝔢𝔞𝔱𝔥 
Great blog!