Madog ap Maredudd (d 1160), prince of Powys, was the son of Maredudd ap Bleddyn ap Cynfyn and nephew of Iowerth ab Bleddyn. His father, who at his death in 1132 was lord of all Powys. The son Madog, if he did not at once succeed to his father's position, doutless attained it before long, and held it for some years. The contemporary poet, Gwalchmai speaks of the influence of Madog as stretching from Plynlimmon to the gates of Chester, and from Bangor to the extremity of Meirionydd i.e. over all Powys; the same idea prevailed, too, as to the extent of his power when (probably at the end of the twelfth century) the story of ;Fhonabwy's Dream' was cast into its present form. According to Powel, on the other hand, Madog ruled only over Northern Powys, which thus got its title of Powys Fadog. Maredudd, Powel tells us, 'had two sons, Madoc . . . and Gruffyth, betweens whom Powys was dinided;' but the fact is that Gruffydd died before his father in 1128. As to the name Powys Fadog, it clearly came into existence at the same time of Powys Wenwynwyn, viz. about the beginning of the thirteenth century, when Madog ap Gruffydd Maelor and Gwenwynwyn ruled Northern and Southern Powys respectively. Madog ap Maredudd was certainly lord of Powys Wenwynwyn, for about 1149 he gave Cyfeiliog, one if its regions, to his nephews, Owain and Meurig ap Gruffydd, and in 1156 he built at sronghold in Caer Einion, which was also a region of Southern Powys.
Madog was prince of Powys during the reign of Stephe, the period during which the Welsh shook off the rigid control established by Henry I, and regained much which they had lost through the Noman conquest. Like other Welsh princes, he seems to have profited by this movement. About 1149 he rebuuilt the castle at Oswestry, a spot which had not been Welsh ground for nearly a century, and which was soon recovered by the English. Madog's appearance in the district was probably directly due to the turmoil caused by the civil war, for Oswestry was part of the Fitzalans' territory and William Fitzalan took active part on the side of the empress. Rhys Cain's attempt to represent the Fitzalans as teh new-comers is discredited by it s gross anachronisms.
The salient feature of Madog's career is not, however, his success against the English, but his friendship with them. During the first half of the twelfth century Gwynedd had been gradmaclly growing at the expense of the minor northern principalities, until in Madog's time it was a formidable neighbour to Powys, conterminous with it from Machynlleth to Chester. Madog first adoped the policy, which afterwards became popular with princes of Powys, of protecting his realm by cultivation the friendship of his English neighbors. In the year in which he had fortified Oswestry, his neighbour, Owain Gwynedd, had built a castle in Ial, always reckoned a district of Powys. The encroachment called for immediate notice, and in the followin year (1150?) Madog enlisted the aid of Ralph, earl of Chester in an attacke upon the prince of Gwynedd. The battle was fought at Consillt, near Flint, and proved a signal victory for Owain. Foiled in this first enterprise, Madog nevertheless adhered to his policy. In 1157, when Henry II made his first expedition into Wales, Madog took no part in the national resistance organised by Owain Gwynedd, but watched the conflict as a spectator, probably in virtue of a secret understanding with the king. The chronicle known as 'Brut y Saeson' says that Madog was commander of the fleet which attacked Anglesey in the course of the campaign, but this statement, in itself improbable, is made by no other authority, and probably arose through the confusion of two consecutive sentences in 'Brut y Tywysogion.' What the latter (and better) authority says of Madog is that 'he chose a place for encampment betwen the king's host and Owain's, that he might receive the first onset the king should make' - a sarcastice description, probably of Madog's real attitude of armed neutrality. It is not without significance that one resulf of the campaign was that Iorwerth the Red, Madog's brother, was enabled to destroy the obnoxious castle in Ial.
Madog died in 1160, and was buried in the church of St Tyailio at Meifod. His son Llywelyn died almost immediately afterwards; other children who survived him longer were: Gruffydd Maelo (d 1191), Owain Fychan (d 1186), Elise, Owain Brogyntyn, Marred, who married Iowerth Drwyndwn, and Gwenllian, who married the Lord Rhys. The genealogists add Cynwrig Efaill and Einion Efaill. The 'Myvyrian Archaiology' contains two contemporary poems in honour of Madog by Gwalchmai and four by Cynddelw Brydydd Mawr. [Dictionary of National Biography XII:745-6
Ancestry/Jane Williams Flank
Ancestry - Errol Bevan
Ancestry - Kirk Larson
wikipedia.org (Rhys ap Gruffydd)
http://experts.about.com/e/1/li/List_of_rulers_of_Wales.htm