BRONLLYS TOWER, on the left bank of the Llyfni, a tributary of the Wye, is situate in the parish of the same name, close north of the town of Talgarth, on the regular and ancient way between Hereford and Brecknock.

The tower occupies the summit of a mound or knoll of earth, in great part artificial, which crowns the steep bank of the adjacent river; rising, perhaps, 60 feet above the stream, and 30 feet or so above the ground to the west of and behind the building. The mound is placed at the apex of an earthwork of rather a pear-shaped outline, of which the river-bank forms the steep east side, while to its base, or north face, has been applied a vallum nearly rectangular, and which may or may not be a Roman addition to a Celtic camp. The mound, which has borne the very considerable weight of the tower in safety, must be of considerably earlier date; and altogether the work resembles much one of those numerous instances in which advantage has been taken of an earlier mound to give elevation to a Norman or early English keep.

There are, however, it is said, remains of masonry, of the character and probable age of the tower, still standing upon a part of the vallum, and indications that, as is known to have been the case, the tower did not stand alone, but was within a base court. These walls are not now of any extent, and seem to be included within a modern house built upon the old enclosure.

This tower is at its base 37 feet in diameter, and batters inwards to 12 feet high, when it is girt by a bold cordon or string-course, much eroded, but apparently of a half-round section, with a water-groove on its under side. Above this the tower is cylindrical, and 34 feet diameter, or very nearly so, to the summit, which is at present about 60, and may have been 70 feet high. Besides the battering base there is a slight rough set-off, apparently part of the foundation, above ground on the southern face. Round the whole is a walk of about 18 inches broad, so that the mound is about 40 feet across at its top.

The tower is composed of a basement and three floors, above which was the battlement, now completely destroyed. The basement within was cylindrical, 18 feet diameter, with walls 9 feet 6 inches thick, and covered by a pointed vault, the ridge of which runs about north-east and south-west. This room was aired rather than lighted by a stepped recess, terminating in a small loop or hole at a considerable height, through which nothing could be seen. It was entered on the opposite or west side by a trap door in the first floor, which lifted within a window recess, and disclosed a flight of eight very steep stairs, 2 feet 7 inches broad, terminating in a doorway rather above 7 feet from the floor; below which, therefore, was probably a wooden ladder. The rebate shows the door to have opened inwards, and to have had bolts on its outer side. The floor is on the level of the top of the mound, and in its centre is a depression which may indicate a well.

Two openings have been broken into this chamber from the outside, on the east and west sides. Why nine feet of masonry should have been twice pierced, at immense labour, it is difficult to say; nor is there any trace of door or loop which might have made the task easier, or have suggested these openings. The broken walls do, however, show at the very base of the structure, on each side, a horizontal or nearly horizontal square drain, of very rough construction, in the substance of the wall. These holes have been the subject of much speculation. They were evidently drains from the upper floors of the tower, collected to fall into one outlet. Such drains may be seen in the heart of an overthrown solid tower at Corfe. It is not improbable that one of the breaches may have contained a recess or garderobe, which communicated with the drain, and suggested the penetration of the wall in that direction.

The first floor, of 17 feet 9 inches clear diameter, was entered by an exterior door in the wall, at the level of the cordon, or 12 feet above the ground, on the east side. There must have been exterior steps; but they did not bond into the wall, and may have been of wood. The door has 3 feet 3 inches opening, with a drop arch and plain chamfered moulding. It was defended by an interior door; but there was no portcullis or other defence. The door-recess is 4 feet broad, and has a drop arch.

This floor had two windows towards the north and south-west, the openings of which are about 18 inches broad, with plain equilateral heads. The former opens from a recess 7 feet 4 inches broad, having stone side-seats; between which, in the floor, is the trap descending into the dungeon. The other window has a recess 6 feet 10 inches broad, with a stone seat on its left side. In its right, or west jamb, is a door 2 feet 5 inches wide, square headed, beneath a drop relieving arch; from which rises a mural stair 2 feet 5 inches broad, lighted by two exterior loops, and with a flat covering, leading to the second floor. The window recesses are segmental, and are formed of excellent limestone tufa ashlar.

The second story had a timber floor resting on twelve corbels, and is cylindrical, like the first, and of the same diameter, but higher. It was the best room. Besides its entrance door on the west, it has on the south-west a fireplace under a flat segmental arch with plain chamfer, above which are two slender octagonal corbels, which evidently supported a hood, probably of timber. There are also two windows beneath drop-arch recesses, towards the south-east and north-east. The former has stone seats; and the latter a light 2 feet broad, with a cinquefoil head, of which the central foil is an ogee. The head is made of two stones only. The moulding is plain, having a shutter rebate inside; and outside, rounded jambs in place of the usual chamfer. This recess has a stone seat on the west side only. In the east jamb is a small square-headed door opening upon a mural stair of 2 feet 5 inches broad, of which nineteen steps remain, and which led to the third floor.

The stair is lighted by a small hole below, and above by a square-headed loop of 9 inches in a recess splayed to 3 feet 7 inches opening. The loop, though about 60 feet from the ground, was closed by one vertical and three horizontal bars. This floor may have been used as a prison.

The third stage has walls 8 feet thick, and had a wooden floor. The stair from below opened into it on the south-east side, but seems to have been continued in the south wall, so as to reach the battlement platform, now entirely gone. This floor has a small mural chamber, no doubt a garderobe, on its west side, the door into which is narrow, and has an arch of two stones, which seems to be four-centred, or of Tudor pattern. This door is placed between a window on the north-west, the recess of which has a flat drop arch; and another on the south-west, of which the recess is broken away. There is also a small fireplace on the north side, and another window to the north-east.

In the wall close south of the mural chamber are two small square shafts, one of which was no doubt a chimney and the other perhaps a garderobe vent from the battlements.

Bronllys Tower presents divers peculiarities. Though of rude masonry, its door and window dressings are excellent. In general design it resembles early English work; but its doors, recesses, fireplace, and corbels, seem of early Decorated, and perhaps, in parts, of Perpendicular work. It is altogether superior in detail to Penrice, which it resembles in dimensions, and it is inferior to Tre-Tower. The walls may be safely assigned to the first quarter of the thirteenth century; but it was no doubt inhabited as a place of defence, and afterwards as a dwelling, for two centuries and a half after this; and from time to time it received certain alterations, of which the present fireplace-front, the cinquefoiled and other windows, and the entrance to the mural chamber in the upper floor, may be cited as instances. The vault of the basement is possibly original, but may be an addition.