'Madog ap Gruffydd Maelor, Prince of Powys Fadog -1236. Madog consolidated his fathers posessions and the territory he ruled became known as Powys Fadog in his honour - Fadog being a mutation of his name. He married Isota and died in 1236 (buried at Valle Crucis Abbey). he had issue:

• Gruffydd Maelor II, who succeeded his father,

• Gruffydd Lal, died 1238.

• Maredudd, died 1256.

• Hywel, died 1268.

• Madog Fychan, died 1269.

• Angharad.