Gwrtheyrnion

For most of the medieval era, it was associated with the cantref of Buellt and then Elfael, small regional kingdoms whose rulers operated independently of other powers.

According to the 9th-century Historia Brittonum, Gwrtheyrnion, here Latinised Guorthegirnaim, was named after Vortigern (Welsh: Gwrtheyrn), a legendary 5th-century King of Britain.

[2] Generally, its boundaries were the cantrefi of Arwystli to the north, Maelienydd (in its restricted sense) to the east, Elfael to the southeast, and Buellt to the southwest.

[4] One of the text's copyists, from whose copy most other surviving manuscripts are derived, took particular interest in this combined kingdom, tracing its medieval rulers back to Vortigern through Pascent.

Elystan Glodrydd conquered the adjacent land between the Wye and Severn - Ferlix (known also by various other spellings, such as Fferllys, Fferleg, and Fferregs) and incorporated it into his own realm.

Hence, in 1080, when a revolt broke out in Northern England, the Normans pre-emptively occupied Wales, to prevent any further Welsh assistance to the Saxons.

Einion's other brother, Iorwerth Clud, was able to depose Gwalter with the aid of Reginald de Braose (who had, by now, inherited Buellt), in alliance with Llywelyn Fawr (the most powerful Welsh prince).