Powys Fadog (English: Lower Powys or Madog's Powys) was the northern portion of the former princely realm of Powys, which split in two following the death of Madog ap Maredudd in 1160. The realm was divided under Welsh law, with Madog's nephew Owain Cyfeiliog inheriting the south (see Powys Wenwynwyn) and his son Gruffydd Maelor I, who inherited the north. Gruffydd received the cantref of Maelor and the commote of Iâl as his portion and later added Nanheudwy, Cynllaith, Glyndyfrdwy and Mochnant Is Rhaeadr. This northern realm became known as Powys Fadog after the accession of his son Madog ap Gruffudd in 1191 who reigned until 1236, and after whom it may be named (see alternative translations above). During his reign, Madog initially adopted a neutral position between Gwynedd and England but by 1215 had settled on an alliance with Llywelyn ab Iorwerth of Gwynedd. This policy of alliance with Gwynedd altered under his successor Gruffudd II over his thirty-three year reign (1236-1269); pressure from an ambitious Gwynedd, and Gruffydd's marriage to the daughter of an English landowner, caused him to seek support from the English king. However, support from England failed to arrive and in 1258 he was forced into an alliance with Llywelyn ap Gruffudd. Gruffydd's influence waned and Llywelyn was recognised as Prince of Wales under the terms of the 1267 Treaty of Montgomery; Gruffydd subsequently confined himself to building his castle at Dinas Brân. When Gruffydd died in 1269, his eldest son Madog II succeeded to the throne but the small portion of the realm awarded to his younger brothers caused rebellion in which England became engaged. By 1276 Powys Fadog was in disorder with brother fighting brother, and this conflagration soon became a small part in the campaign being waged by the English Crown against the fragile Welsh confederation. In early 1277 an army led by the Earl of Warwick with support from the treacherous brother of Llywelyn ap Gruffudd, Dafydd ap Gruffydd, marched from Chester into Powys Fadog. Madog II was compelled to submit and under the terms of his surrender the realm would be divided between himself and his younger brother Llywelyn. The royal centre at Castell Dinas Brân, widely considered the strongest native castle in all Wales, was to be had by neither and dismantled. It appears that Madog II (or at least men loyal to him) remained at Dinas Brân for