A rebellion started in 1400, during the rule of Henry IV. It was started by Owain Glyndŵr. This was just after Richard was told he was no longer king. Two cousins of Owain Glyndŵr, Rhys ap Tudur and his brother Gwilym, attacked the castle as a surprise. They dressed up like carpenters and acted like they were going to fix the castle. The got inside, killed two watchmen, and took over the castle. Their troops took over the town. The brothers lived there for about 3 months. They gave up after Henry IV promised to forgive them and they would not go to trial.