Bronllys Castle

A round tower on a steep-sided mound, standing to three storeys, in a field beside the Llynfi a mile and a half from Talgarth.

It is small, it is complete enough to climb, and it is one of the clearest surviving examples in the Marches of a particular twelfth- and thirteenth-century idea: put a circular stone keep on top of an existing earth motte and you get most of the benefit of a stone castle without rebuilding from the ground up.

Why circular

Square towers have corners, and corners can be undermined. A miner working under an angle brings down two walls at once. A cylinder has no such weakness, distributes load evenly and gives defenders a continuous field of fire.

Round keeps became common in the Marches and in south Wales in the decades either side of 1200, and there is a cluster of them within a short distance of here — Tretower, Skenfrith and Caldicot among them.

The building

The keep is of the early thirteenth century, replacing an earlier timber structure on the same motte. The motte is Norman and considerably older, raised by the Clifford family who held Bronllys from the eleventh century.

Entry was at first-floor level, as it almost always was, reached originally by a removable stair. Inside there are three storeys with a fireplace and window seats on the upper floor, which is where the lord's chamber would have been.

The bailey below has been largely ploughed and built over, so what survives is the keep and its mound, isolated from the rest of the castle it belonged to.

Later

The castle was held with Talgarth as part of the lordship of Brecon and passed through several families. By the fifteenth century it was redundant as a fortress.

The stone survived because there was no town here to quarry it, which is exactly what happened at Builth twenty miles west, where an Edwardian castle was taken away entirely.

Visiting

Cadw, free, open access, with a small parking area on the lane. There is a stair to the top of the keep and a good view over the Llynfi valley to the Black Mountains.

Talgarth is a mile and a half north-west, and the Mid Wales Hospital site and Trefeca are both nearby.