Cadafael renewed Cadwallon's alliance with Penda and the other Welsh kings, and the wars against Northumbria continued in the north and the English Midlands. Sometime between 635 and 641 Penda defeated the
Kingdom of East Anglia and killed
King Egric. He would also kill Egric's successor
Anna in 654, establishing himself as the dominant power in the region. The most significant action occurred at the
Battle of Maserfield () in 642/644, assumed to be near
Oswestry. There Penda and his Welsh allies defeated and killed
Oswald. The wars went less well in the north. Northumbria secured the entire eastern coastal region of
Lothian (i.e.,
Gododdin) in 638 or shortly thereafter, and there were battles against the men of
Alt Clud (the Brythonic predecessor state of
Strathclyde) in the 640s. While the outcome of these battles is not given in the historical record, most of what is now southern
Scotland came under Northumbrian control, suggesting Northumbrian success. However, Penda and his alliance was still a major threat, and they besieged Oswald's Bernician successor
Oswiu at his fortress of
Bamburgh in 650 or 651, though they did not defeat him. The defining moment came in 655 when Penda again led an alliance of Mercians, Welsh, Deirans, and East Anglians against Bernicia, besieging Oswiu at a stronghold somewhere in the north and compelling him to sue for peace. Having won this war at great cost, the members of the alliance returned south, the Welsh, in particular, pleased to have reclaimed items of dignity (the so-called "Restoration of Iudeu") taken from the kingdom of Gododdin or Manaw Gododdin by the Northumbrians. However, while Oswiu had been beaten he had not been defeated. With many of its leaders having been killed in battle, the alliance was caught unawares in a sortie by Oswiu at
the Winwaed (, its location uncertain). Penda was killed, thus ending the alliance and ensuring a Bernician supremacy. Oswiu quickly followed up his defeat of Penda by overrunning Mercia and launching a surprise assault on
Pengwern's
llys (), killing
King Cynddylan and virtually wiping out the entire royal family. Thereafter Pengwern disappears from the historical record, with some of its survivors moving westward to
Mathrafal, and any who remained becoming part of a Mercian subkingdom. == End of an epoch ==