Cadwgan ap Bleddyn was a prince of the Kingdom of Powys in eastern Wales. Cadwgan was the second son of Bleddyn ap Cynfyn who was king of both Powys and Gwynedd. When Bleddyn was killed in 1075, Powys was divided between three of his sons, Cadwgan, Iorwerth and Maredudd. Cadwgan is first heard of in 1088 when he attacked Deheubarth, forcing its king, Rhys ap Tewdwr, to flee to Ireland. However Rhys returned later the same year with a fleet from Ireland and defeated the men of Powys in a battle in which two of Cadwgan's nephews, Madog and Rhiryd, were killed. When Rhys ap Tewdwr was killed in 1093, Cadwgan again attacked Deheubarth, but it soon became clear that it was the Normans who would benefit from the death of Rhys. About this time Cadwgan married the daughter of one of the neighbouring Norman lords, Picot de Sai. In 1094 a Welsh revolt against Norman rule broke out, and Cadwgan played a part in this, defeating a Norman force at the battle of Coed Yspwys. Bleddyn was now an ally of Gruffudd ap Cynan, king of Gwynedd, and when Earl Hugh of Chester and Earl Hugh of Shrewsbury launched an invasion in 1098 to try to recover Anglesey for Hugh of Chester, Cadwgan was with Gruffydd. A Danish fleet hired by Gruffudd was offered a higher price by the Normans and changed sides, forcing Cadwgan and Gruffudd to flee to Ireland in a skiff. They were able to return to Wales the following year, and Cadwgan was able to reclaim part of Powys and Ceredigion, on condition of doing homage to Earl Robert of Shrewsbury. For a while Cadwgan was able to strengthen his position. Earl Robert fell out with the king in 1102 and was defeated with the assistance of Cadwgan's brother Iorwerth. Iorwerth took his other brother, Maredudd, captive and handed him over to the king. However many of the lands which Iorwerth had been promised in exchange for his help were given to Norman lords instead, and Iorwerth broke with the king. In 1103 he was arraigned before a royal tribunal and imprisoned, leaving Cadwgan as sole ruler of the parts of Powys not in Norman hands. However, in 1109 Cadwgan's son, Owain ap Cadwgan, fell in love with Nest, wife of Gerald of Pembroke and launched a daring raid on the castle of Cenarth Bychan to abduct her. Cadwgan tried to persuade his son to return Nest to her husband but failed. The justiciar of Shropshire, Richard de Beaumais promised members of other branches of the ruling house of Powys extensive lands if they would join in an attack on Cadwgan and Owain. Ceredigion was invaded and Owain fled to Ireland, while Cadwgan made his peace with the king but was allowed to hold only one border vill. King Henry I of England later allowed him to have Ceredigion back on condition of paying a fine of £100 and promising to have nothing to do with Owain in future. When his brother Iorwerth was killed by Madog ap Rhiryd in 1111, Cadwgan again briefly took over the rule of all Powys, but later the same year Cadwgan himself was also killed by Madog at Welshpool. Madog was able to seize some of his lands, while the remainder fell to his son Owain.
