Photo by Charles Taylor, courtesy of http://www.ecastles.co.uk/abergavenny.html
When researching a specific time and place in preparation for writing historical fiction, some events stand out in your memory and nag at the back of your thoughts. The event may be a few years off from your own story, it may involve people who you have not included, but it nags at you anyway. And like the gravitational pull the boulder in the middle of the trail has on your mountain bike, the event pulls your story toward it somehow. It's that compelling. It will not be ignored.
The Massacre at Abergavenny is one of those events. J.E. Lloyd had this to say about it in his History of Wales:
"The border warfare was at all times savage and unpitying, but it did not often witness perfidy and barbarity of this deep dye; small wonder was it, men thought, that misfortune should beset the path of the lord of Abergavenny."
In December of 1175, William de Briouze, 4th lord of Bramber, stepped into his inheritance as the lord of Brecknock. Already a wealthy landholder, the younger William took up his role while his father, William de Briouze, 3rd lord of Bramber, still lived. Aged either 22 or 31 years old, already a father himself with his wife of nine years, the twenty-year-old Maud St. Valery, young William decided to make a statement for himself during that Christmastide.
The young lord invited three Welsh princes to his castle at Abergavenny under the pretense of hearing a royal ordinance as to the bearing of arms. The princes, their accompanying sons and attendants all handed over their arms as they entered the castle--a sign of trust and peaceful intentions that was generally observed as a rule when entering a castle on the host's invitation (as opposed to a siege). One wore one's sword on the road while travelling, but in taverns, churches, and a host's home, swords and weapons were deposited for safekeeping for the length of the stay.
In this case, once the guests were all assembled inside the great hall, the doors were barred and every single man was cut down. William and his attendants then hopped onto their swiftest horses and sped south a few miles to the country of Seisyll ap Dyfnwal, one of the slain. De Briouze arrived ahead of the news of the slaughter, found Seisyll's wife, executed the youngest son, seven-year-old Cadwaladr, in her arms, and left the wife and mother to a fate unrecorded in the historical legend.
As is often the case in savagery, blood vengeance directed the perpetrator. William's motive is said to have been revenge for the murder of his uncle, Henry FitzMiles, allegedly murdered by Seisyll while visiting Siesyll's castle. But more than that, it has been suggested that William sought to eliminate the leadership of the Welsh lands that surrounded him, to weaken and destabilize the local families and thus ensure his own family's security. And as is often the case with blood vengeance, further acts answered the earlier acts. Abergavenny Castle was burnt to the ground by the Welsh men of Gwent in retribution for the massacre carried out there just a few years later; the picture shown above shows the ruins of the subsequent castle built on the earlier castle's ashes. English reinforcements arrived afterward to restore order and William himself escaped capture, but the Welsh carried the day in the end.
William de Briouze's ignominious career carried him in his later years into King John's court, where he became one of the chief suspects (aside from the king himself) in the disappearance and suspected murder of the young Arthur of Brittany, the king's strongest rival for the throne. King John, being John Plantagenet, later changed his favorable feelings toward de Briouze. Eventually William's wife and son would die of starvation in the king's custody, most likely in Corfe Castle, and William himself would die penniless and fallen, alone in exile.
If this tale brings to mind the stories of George R.R. Martin, you are not alone. Game of Thrones is fantasy fiction at it's pseudo-middle-ages goriest, but Abergavenny still resounds through the historical record as an especially dire moment of Norman brutality in the Welsh Marches.