Skenfrith Castle is the only low-lying fortress of the of her sister castles Grosmont and White Castles, built to protect one of the main routes through the border region between England and South Wales. In the late 1130's King Stephen brought all three castles together under a single Lordship that controlled the 'Three Castles' as one defensive unit.

The castle is built on level ground by the banks of the Monnow. The curtain walls form a large, irregular quadrangle  with round towers at each corner. There were a range of domestic buildings including a hall on the western side, and in the middle of the courtyard is a circular keep. The keep has a sloping battered base and a semi-circular projection from the wall that contained a spiral stair that led to two storeys above a basement. Earth was piled around the tower after it was completed giving the false impression that it is built on a mound.

Although dry now, the curtain walls would have been surrounded by a moat 9 feet deep and 46 feet across, beside which the River Monnow would often flood. Built upon an artificial platform of gravel up to 12 feet thick in places, from the earlier timber castle which was destroyed to make way, Roman pottery has also been found.

~ History ~

1067 - Following William the Conqueror's successful invasion of England, he makes one of his principle supporters, William Fitz Osbern, Earl of Hereford. Fitz Osbern builds his new castles at Chepstow and Monmouth.

1071 - Fitz Osbern dies in the Battle of Flanders.

1075 - Fitz Osbern's son rebels against King William and his lands are forfeit to the Crown. To avoid a single powerful magnet taking single control of such a strategically important area again as the Fitz Osbern's had done, the Crown grants away their lands and castles piecemeal fashion.

1135 - Upon King Henry I's death, the Welsh rebel against the Normans on the southern March.

1138 - King Stephen reunites the territories of the Three Castles into a single lordship so as a more co-ordinated defence under a single lord, loyal to the Crown can be made.

1182 - The Welsh attack Upper Gwent, burning Abergavenny Castle, save only the keep, and kill the Sherriff of Hereford, in an area between Monmouth and Skenfrith, where he is building an earthwork castle.

1187 - Ralph Grosmont, royal engineer to King Henry II, is instructed to rebuild Skenfrith in stone. £43 is spent on repairing the wooden palisades whilst the stone keep is erected. The King cancels this work the following year.

1193 - Sherriff William Braose pushes the unfinished castle into rapid service by placing a palisade around the unfinished walls of the castle.

1201 - King John grants the lordship of the Three Castles to Hubert de Burgh.

1203 - Hubert is away serving his King in France, as constable of Chinon on the Loire. He defends the castle in a year long siege against the French King Philip Augustus.

1205 - Chinon falls to the French and Hubert is captured and kept prisoner of war for the next two years. In the autumn after his capture, King John rewards the loyal service of Hubert by granting away his lordship of the Three Castles to his rival on the March, William de Braose.

1207 - William has now also fallen from power and favour and is being hounded to ruin, and his family to their deaths, by the vindictive King John.

1215 - King John is forced to sign Magna Carta and Hubert recovers much of his lands.

1219 - With the twelve year old Henry III now on the throne, Hubert finally recovers the Three Castles.

1220 - Hubert visits Skenfrith to personally supervise the completion of Skenfrith in stone. Before the year is out the castle is devastated by heavy flooding in the Monnow valley. Hubert therefore fills in the castle with river gravel and the remains of the part finished castle, and sets about building a new stone castle on top of the old one.

1232 - Following years on unsuccessful gains against the Welsh and bitter rivalry with the bishop of Winchester, Hubert is turned out of office and stripped of his lands and recently completed castles, only to be returned to him two years later following the bishops fall from grace.

1239 - Henry III seizes the castle from Hubert over a row concerning Huberts daughters wedding.

1262 - The Welsh under the leadership of Llywelyn attack the neighbouring lordships and the Three Castles are ordered to garrison, 'by every man, and at whatever the cost' by their owner, the future Edward I.

1267 - The Three Castles are granted to Edmund 'Crouchback', Earl of Lancaster. Five years later Edward becomes King Edward I of England and 10 years on Welsh independence is ended upon Llywelyn's death in 1282. The role of the Three Castles and other similar Marcher castles are effectively brought to an end.

1404 - The Three Castles once more see a short return to military action during the Welsh rebellion under Owain Glyndwr. Repairs are made twenty years later to keep the castles in good repair but gradually all three fall into disuse and by 1538 all are abandoned.