Meanwhile Cadwallon had arrived, and through Brian entered into a league with Penda, king of the Mercians, against Edwin. Both forces marched into Northumbria, and a battle was fought at a place called Heathfield, and Edwin was slain and his Northern Angles routed. Then, for a while, Cadwallon reigned over all the British peoples in Wales, Strathclyde, and Devon and Cornwall. He was succeeded by his son Cadwaladr, whose mother was a sister of Penda the Mercian. He was a good and peace-loving prince, not made of the same stuff as his father, and although he gained some victories his reign was marked by loss of ground on all sides. He wore the crown for twelve years. In 664 a terrible plague broke out which spread desolation over Britain and Ireland, and in the latter swept away two-thirds of the inhabitants. Cadwaladr was one of the victims, and was buried in the church that bears his name by Llyn Coron. The church has an east window to the chancel of a flamboyant character, with some old stained glass in it representing the Crucifixion and saints. The line to Holyhead passes a cluster of lakes of not much beauty--that of Llyn Penllyn has a little island in it--then it crosses a causeway into Holy Isle, and draws up at the terminus of Holyhead, under Pen Caergybi, the highest elevation in Anglesey. Ruskin says:-- “Just on the other side of the Mersey you have your Snowdon and your Menai Straits, and that mighty granite rock beyond the moors of Anglesey, splendid in its heathery crest, and foot planted in the deep sea, once thought of as sacred--a divine promontory, looking westward, the Holy Head or Headland, still not without awe when its red light glares first through the gloom.” The cliff scenery here is of the finest quality, and Holyhead well merits a prolonged visit, what with the stimulating air rushing through one’s lungs charged with sparkles, the look-out on the green sea flecked with foam and skimmed by gulls as flakes of froth that have been detached from the waves and become alive, the plunging water on the beach, the purple folds of the hills, and the abrupt cliffs, their feet ever bitten into and worried by the angry waves. The town is as busy as Beaumaris is inert. It lives on the Irish trade, whereas Beaumaris picks up subsistence during a few short months only from bathers.