The Battle of Painscastle

I was stopped the other day by someone who knows of my interest in re-enactment and local history - she wanted to know more about the Battle of Painscastle, which is not far from Hay.
It's not one of the better known battles of medieval history, but it was disastrous for the Welsh.
In 1195, Matilda de Braos's forces caused a "great slaughter" of the Welsh defenders when she took Painscastle - she also built Hay Castle, and her husband William was lord of nearby Huntington.
In 1198, Prince Gwenwynwyn ap Owain of Powys brought up his army to besiege the castle and bring it back under Welsh control, and on 13th August 1198, after mediation had failed, an English army arrived to break the siege, and the justiciar of England, Geoffrey fitz Peter, took the decision to meet Prince Gwenwynwyn in pitched battle.
It was a slaughter. The Welsh forces broke almost straight away and an estimated 3,000 men died - with hardly a man lost on the English side. It was said that the River Bachawy ran red with the blood of the slain. It was one of the biggest massacres in Welsh history, and several of the Welsh princes who accompanied Gwenwynwyn were killed.
After that, the castle passed back and forth between Welsh and English lords, and the earthworks are still impressive. The castle was last in use when it was re-fortified against Owain Glyndwr in around 1400.