The ancient kingdom of Powys had clearly been extensive, though how extensive is difficult to estimate. It was reputed in early poetry, such as Canu Heledd, and in legends that become visible in the twelfth century, to have embraced not only much of mid- and north-eastern Wales but also the territory that was to become Shropshire. After many vicissitudes, including internal dynastic rifts and encroachment into its eastern territories by advancing Anglo-Saxons, punctuated by at least one phase of recovery, the Powysian polity had, it seems, collapsed in the mid-ninth century. Much of the territory over which it had once extended had passed into the control of the kings of Gwynedd or had long since been taken into the hands of the English. The death in Rome in 854 of Cyngen, the last recorded king of the old realm of Powys, was noted in the Welsh annals, and thereafter the polity itself and its royal line disappear from all records. The fact that much of Powys was for approximately a quarter of a millennium a subordinate part of the now extended territories of the ruling house of Gwynedd, and that parts of it were brought under English rule, was almost certainly to have significant socio-political consequences when, after around two and a half centuries, a Powysian kingdom re-emerged, and became one of the principal political units of Wales in much of the twelfth century and throughout the thirteenth.

Something of the situation that had developed by the later eleventh century is revealed in the Latin Life of Gruffudd ap Cynan, the Vita Griffini filii Conani. This introduces two men whose political base is located in Powys: Cynwrig ap Rhiwallon, killed in 1075, who is described as rex Powisiae (king of Powys), and Gwrgeneu ap Seisyll, regulus Powisiae (sub-king of Powys), killed in 1081. The latter is also described as leading an expedition virisque Powisiae (with the men of Powys). Cynwrig is associated in the text with Trahaearn ap Caradog, ruler of Arwystli, who made himself the dominant force in north Wales in the years 1075–81. It is important to note that the links of these figures with the old dynasty of Powys were marginal. Some later genealogical sources appear to suggest that Gwrgeneu ap Seisyll's great-grandfather Gwerystan ap Gwaithfoed had married Nest ferch Cadell ap Brochwel, a sister of the last recorded ruler of Powys in the ninth century.