At the time the Britons abandoned Wroxeter, the situation of Pengwern was one of eminent natural strength. We must not estimate the degree of protection imparted to the place by the Severn from our ideas by the condition of the river in the present advanced state of cultivation. Whenever any country is thinly inhabited, trees and shrubs spring up in the uncultivated fields, and, spreading by degrees, form large forests, which, confining the exhalations of the soil and obstructing the course of streams, cause the rivers to overflow and stagnate into lakes and marshes. The Severn, on the eastern side of Shrewsbury, formerly ran in five channels, and spread into a marshy lake from the foot of Wyle Cop as far as the site of the Abbey. Thus the fugitives were protected by the deep bed of the river, its sinuous windings, and the morasses of its banks, where they might shroud themselves in the underwood which hid the foot, and the thickets which crowned the summit of the lofty and peninsular knoll now covered by the capital of Shropshire. How long the fugitives remained in possession of their new seat it is vain to enquire. But they were followed hither by the Saxons, who reduced the place to ashes, and the elegy of Llywarc calls upon the maidens of Pengwern “To quit their dwellings, and behold the habitation of Cynddylan, the royal palace of Pengwern, wrapped in flames.”
The importance of the peninsular situation of Pengwern could not long remain without an occupant; and a few years after its destruction under Cynddylan, we find it inhabited by a king of Powis, the capital of his kingdom, and even ranking among the twenty-eight cities of Britain. The kingdom of Powis at this time comprised the south-western parts of the counties of Cheshire, Flint, and Denbigh, the whole of Montgomeryshire, with portions of the counties of Radnor, Brecon, and the adjoining parts of Shropshire, as far as the river Severn. Of the state of the town, under its native princes, we possess no information. The arts of civil life, which the Britons had cultivated under their Roman masters, had totally disappeared in the course of three centuries of uninterrupted warfare. A ditch, or a rude rampart of unhewn logs, inclosing a few hovels for the residence of the prince and the offices of religion, some wattled huts, with a fold or two for sheep and cattle, probably composed the whole of Pengwern Powis. On the invasion of the Saxons, the new possessors gave it the appellation of _Scrobbes-byrig_—a fenced eminence, but overgrown with shrubs.