Seisyll ap Dyfnwal was a 12th-century

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peop ...

Lord of Gwent Uwchcoed (Upper Gwent).

Family and estates

Seisyll was the son of Dyfnwal ap Caradog ap Ynyr Fychan and his wife, said to have been Joyce daughter of Hamelin de Balun. He was a brother-in-law of

Rhys ap Gruffydd Rhys ap Gruffydd, commonly known as The Lord Rhys, in Welsh ''Yr Arglwydd Rhys'' (c. 1132 – 28 April 1197) was the ruler of the Welsh kingdom of Deheubarth in south Wales from 1155 to 1197 and native Prince of Wales. It was believed that he ...

, ''the Lord Rhys'', King of

Deheubarth Deheubarth (; lit. "Right-hand Part", thus "the South") was a regional name for the realms of south Wales, particularly as opposed to Gwynedd (Latin: ''Venedotia''). It is now used as a shorthand for the various realms united under the House of ...

. He held lands in present-day

Monmouthshire Monmouthshire ( cy, Sir Fynwy) is a county in the south-east of Wales. The name derives from the historic county of the same name; the modern county covers the eastern three-fifths of the historic county. The largest town is Abergavenny, with ...

, part of the old Welsh

Kingdom of Gwent Gwent ( owl, Guent) was a medieval Welsh kingdom, lying between the Rivers Wye and Usk. It existed from the end of Roman rule in Britain in about the 5th century until the Norman invasion of Wales in the 11th century. Along with its neighbou ...

, and his main base was at

Castell Arnallt The site of Castell Arnallt, sometimes known as Castle Arnold, is located near the village of Llanover in the Usk valley of Monmouthshire, Wales, some south east of Abergavenny. It was the fortified court house, or '' llys'', of Seisyll ap Dy ...

, a

motte and bailey A motte-and-bailey castle is a European fortification with a wooden or stone keep situated on a raised area of ground called a motte, accompanied by a walled courtyard, or Bailey (castle), bailey, surrounded by a protective Rampart (fortification ...

style fortified site situated near the

River Usk The River Usk (; cy, Afon Wysg) rises on the northern slopes of the Black Mountain (''y Mynydd Du''), Wales, in the westernmost part of the Brecon Beacons National Park. Initially forming the boundary between Carmarthenshire and Powys, it fl ...

a few miles south of

Abergavenny Abergavenny (; cy, Y Fenni , archaically ''Abergafenni'' meaning "mouth of the River Gavenny") is a market town and community in Monmouthshire, Wales. Abergavenny is promoted as a ''Gateway to Wales''; it is approximately from the border wi ...

, near modern-day Llanover. It is today just a mound in a riverside field.

Christmas massacre

Seisyll ap Dyfnwal is best known for being an unwitting victim of the

Norman Norman or Normans may refer to: Ethnic and cultural identity * The Normans, a people partly descended from Norse Vikings who settled in the territory of Normandy in France in the 10th and 11th centuries ** People or things connected with the Norm ...

Baron Baron is a rank of nobility or title of honour, often hereditary, in various European countries, either current or historical. The female equivalent is baroness. Typically, the title denotes an aristocrat who ranks higher than a lord or knig ...

, William de Braose, 4th Lord of Bramber, who had him murdered in cold blood on or very near Christmas Day 1175 at Abergavenny Castle. Seisyll, along with all the other Welsh princes and leaders from the area, was invited to Abergavenny Castle at Christmas by William De Braose on the understanding that they could voice grievances, overcome differences and plan a period of relative peace following a period of conflict. Some Welsh leaders stayed away, mistrusting de Braose. Seisyll attended along with his eldest son Geoffrey. Most other leaders followed suit and attended, assured of peaceful intent at the castle and surrendering their arms. Once inside the walls they were cut down without mercy by armed men. De Braose and his men then mounted horses and galloped the few miles to Seisill's home where they caught and murdered his younger son, Cadwalladr a boy of seven years of age and captured his wife, whose exact fate is uncertain. De Braose's act was to avenge his own uncle's death. His uncle Henry FitzMiles, had been a victim of the Welsh earlier in the year. His exact killer was probably unknown but Seisyll was apparently suspected. De Braose's strategy was to eliminate all those who could have done it and effectively remove the experienced leadership of the Welsh forces in the area, destabilising the region and seize the opportunity to gain the upper hand. The effect was to drive a massive wedge into Anglo-Welsh relations for generations to come.

Legacy

The de Braose family name was a byword for dishonourable dealing and de Braose descendants face hatred, fear and enmity from this point on. De Braose himself earned the nickname the 'Ogre of Abergavenny' for his conduct and his follow-up retribution on his enemy's families. Seisyll's death was avenged in 1182 by Hywel ap Iorwerth, the Welsh lord of Caerleon, in a campaign in which the sheriff of Hereford was killed and Abergavenny castle stormed. De Braose's son and heir later fell from royal favor, dying in exile, and his wife and son were possibly starved to death while incarcerated at

Windsor Castle Windsor Castle is a royal residence at Windsor in the English county of Berkshire. It is strongly associated with the English and succeeding British royal family, and embodies almost a millennium of architectural history. The original cast ...

and Corfe Castle in 1210.

References

{{DEFAULTSORT:Seisyll Ap Dyfnwal 1175 deaths People from Monmouthshire Welsh royalty Year of birth unknown