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Tomen y Castell is a medieval motte situated in Wales and protected by Cadw under reference CN196. The earthwork rises from bedrock composed of felsic tuff, an Ordovician extrusive rock formed over 440 million years ago during the early Palaeozoic. This volcanic substrate, exposed across much of Wales, provided a naturally hard foundation for the motte's construction, which may have influenced both its siting and structural integrity.
The motte consists of a raised artificial mound, the characteristic form of early medieval military architecture in Wales and the Marches. Such structures typically date from the late 11th to 13th centuries and served as strongholds for Norman and Anglo-Norman lords consolidating control over Welsh territories. The mound would originally have been crowned with a timber or stone palisade and a central keep or hall.
The monument's survival on the Ordovician bedrock reflects the durability of both the underlying geology and the medieval engineering principles that exploited it. Tomen y Castell remains an important example of the military landscape that emerged following Norman expansion into Wales, demonstrating how natural geology and human fortification strategies combined to shape medieval defence systems.
Tomen y Castell is a scheduled monument protected by Cadw under reference CN196. View the official record →
Tomen y Castell is a medieval motte situated in Wales and protected by Cadw under reference CN196.
Tomen y Castell dates from the medieval period, and is classified as a motte. It is one of over 32,000 scheduled monuments protected across the UK.
Tomen y Castell is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is CN196.
Several scheduled monuments lie within 10 km, including Rhiwbach Quarry, Tramway and Incline System (5.6 km), Diffwys Quarry (6.3 km), Oakeley Quarry Tips (6.5 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Tomen y Castell's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Tomen y Castell stands on Unnamed Extrusive Rocks, Ordovician, bedrock that formed in the Ordovician. The rock here is felsic tuff.