Eryrys (Erw Yrys) - From 'A Topographical Dictionary of Wales' (1849)
ERYRYS (ERW YRYS), a hamlet, in the parish of Llanarmon, union of Ruthin, hundred of Yale, county of Denbigh, North Wales, 4½ miles (E.) from Ruthin; containing 681 inhabitants. This hamlet, which takes its name from Yr Hên Gyrys o Iâl, a collector of Welsh proverbs in the eleventh century, forms the northern portion of the parish, and is situated in a narrow valley watered by the river Alyn. It is bounded on the western side by the lofty Clwydian mountains, which separate it from the Vale of Clwyd, and on the eastern by a range of hills, nearly equal in height, separating it from Flintshire. The latter exhibit several projections of limestone rock, highly impregnated with lead-ore, mines of which have been worked for many years: in 1828, a very powerful steam-engine was erected, for pumping out the water. The road from Caergwrle to Ruthin passes through the hamlet, nearly parallel with the river Alyn, which is here crossed by a bridge, and then continues its course towards the latter town between two lofty mountains, called Moel-Venlli and Moel-y-Cyw, each upwards of 1715 feet above the level of the sea: this gap is called Bwlch Agricola, from an opinion that it was traversed by Agricola on his route to Mona. On an artificial mound near the foot of the former mountain stood the castle of Iâl, built by Owain Gwynedd, in 1148, of which the only remains consist of the rampart and fosse surrounding it.