Summary Description and Reason for Designation
The following provides a general description of the Scheduled Ancient Monument.
The monument consists of the remains of a castle dating to the medieval period. Newcastle is strategically placed on a high bluff above the Ogmore Valley guarding the river crossing below. The original castle, first mentioned in 1106, marked the western limit of Robert Fitzhamon's conquests. It is thought to have been an earthwork castle of ringwork type, and its location is unknown. It could have been on the site of the present castle, in which case its palisade may have underlain the later stone curtain wall. The round-cornered stone building, the foundations of which are visible in the south-east corner of the interior, could, on stylistic grounds, date from this initial phase, and might have been a keep; in the 19th century a stony mound was recorded here which was interpreted by G.T. Clark as the ruins of a free-standing keep. Rebuilding in stone probably took place during an unsettled phase in the 1180s, when the king himself, Henry II, held the castle. The layout and style of stonework are of this period, and the fact that it was in royal hands would explain its superior quality.
Apart from refurbishments in the south tower in the late 16th century the castle is virtually untouched since the late 12th century: in 1217 it was given to the Turbeville, Lords of Coity, who had little use for it as their main seat was nearby Coity Castle. The castle's most outstanding feature is its complete Norman doorway, which is on the south. It is late 12th century, contemporary with the curtain wall. On the inside it is quite plain, but the outside is given fine decorative treatment. Sutton stone is used, as it is for the high-quality ashlar facing still in place around it, and also for all other quoins and dressings in the castle. A round-headed arch over attached columns with crude ionic capitals frames the doorway, around which is a shallower segmental arch surrounded by sunken rectangular panels and 'pellet' decoration. This is a rare survival from the period, and no other decoration of the kind is known in Glamorgan. The steps in front are modern.
Once inside the curtain wall it becomes apparent that it is a courtyard castle. It is roughly circular in plan, with two mural towers built into the curtain wall on the south and west sides, and originally a few buildings on the edge of the north and east sides. The curtain wall, which was built in straight sections, is impressive and stands to its full height on the west side. On the outside it was strongly battered at the base, and this batter is still visible, although most of the facing stone has gone from the lower parts of the walls, and from all of the east wall.
The square mural towers were a new development in military planning when built, but were soon to be superseded by round towers. The south tower is the better preserved, standing in parts three storeys high. It was much altered for domestic use in the late 16th century, when Tudor windows and fireplaces were inserted. Only the ground floor of the west tower survives. Very fragmentary foundations of a detached building at the north end, and the more complete foundations of two buildings against the east curtain wall are visible. The small, northernmost one of these is thought to be early 13th century, while the larger, southernmost one is possibly the keep of the initial phase.
The monument is of national importance for its potential to enhance our knowledge of medieval defensive practices. The monument is well-preserved and an important relic of the medieval landscape. It retains significant archaeological potential, with a strong probability of the presence of both structural evidence and intact associated deposits.
The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.