In Northumbria in Offa's closing years we also hear of piratical raids. In June 793 heathen men, whether Danish or Norse cannot be decided, ravaged the church at Lindisfarne and captured many of the monks to sell as slaves. Next summer they came again and attacked Wearmouth and Jarrow where Bede had spent his days. These inroads however did not continue, nor can they have disturbed the Northumbrians very much. For the magnates of Bernicia and Deira for many years past had been flying at each other's throats with wearisome monotony. Harryings and burnings had become the rule, and king after king had met with deposition or a violent death. Aethelred, son of Moll, held the throne when the heathen ships appeared. He had married Offa's second daughter, and, like Beorhtric, may be regarded as almost Offa's vassal; but the alliance had brought him little strength. In 796 he was murdered at Corbridge on Tyne. His inmediate successor reigned for only twenty-seven days, and then fled making way for Eardwulf, a prince whose reign of ten years (796-806) is merely a chronicle of plunderings and executions ending in his deposition. Clearly it is useless to peer into the gloom and turmoil of the North in these days. One event only seems of importance as it affected the ultimate position of the boundary of England. It was in these years that the Galloway bishopric of Whithern (Candida Casa), hitherto subject to York, came to an end, the Picts of this district throwing off their subjection to the English and uniting with the British kingdom of Strathclyde.
Coenwulf ruled over Mercia for a full quarter of a century (796-821). On the whole he shewed himself a man of resource and energy; but his reign was not without its difficulties, and he seems to have been unable to reap any advantage either from the want of enterprise of the West Saxons or from the chaos which reigned among the Northumbrians. In his days nothing occurred to alter the balance of power in England. Mercia remained the leading state; nor is there any record of attacks on its coasts by sea rovers. The king's first recorded activity is a war against the North Welsh, which led to a battle at Rhuddlan. We learn this from the Annales Cambriae. As this campaign was followed up later in his reign by another against the South Welsh, it may be useful at this point to say a few words about the general condition of Wales in the years that followed the building of Offa's celebrated boundary dyke. Our information is scanty, but sufficient to prove that the land was subdivided into many chieftaincies or so-called "kingdoms." The most important tribal units, counting from North to South were (1) Gwynedd or North Wales (in Latin Venedotia), (2) Powys, (3) Ceredigion (Cardigan), (4) the promontory of Dyfed (in Latin Demetia), (5) Ystrad Tywi (the Vale of the Towy), (6) Brycheiniog (Brecknock), (7) Morgannwg (Glamorgan), and (8) Gwent (Monmouthshire). The traditional primacy or overlordship over these and many other smaller units lay with the kings of Gwynedd, whose territories comprised the
