In a few years the English church became the pride of Western Christendom. Not merely did it produce the great band of missionaries who converted heathen Germany--Willibrord, Suidbert, Boniface and the rest--but it excelled the other national churches in learning and culture. It is but necessary to mention Bede and Alcuin. The first, as has been already said, was the one true historian who wrote during the dark time of the 7th-8th centuries; the second became the pride of the court of Charles the Great for his unrivalled scholarship. At the coming of Augustine England had been a barbarous country; a century and a half later she was more than abreast of the civilization of the rest of Europe. Formation of the kingdoms. But the progress toward national unity was still a slow one. The period when the English kingdoms began to enter into the commonwealth of Christendom, by receiving the missionaries sent out from Rome or from Iona, practically coincides with the period in which the occupation of central Britain was completed, and the kingdoms of the conquerors assumed their final size and shape. Æthelfrith, the last heathen among the Northumbrian kings, cut off the Britons of the North from those of the West, by winning the battle of Chester (A.D. 613), and occupying the land about the mouths of the Mersey and the Dee. Cenwalh, the last monarch who ascended the throne of Wessex unbaptized, carried the boundaries of that kingdom into Mid-Somersetshire, where they halted for a long space. Penda, the last heathen king of Mercia, determined the size and strength of that state, by absorbing into it the territories of the other Anglian kingdoms of the Midlands, and probably also by carrying forward its western border beyond the Severn. By the time when the smallest and most barbarous of the Saxon states--Sussex--accepted Christianity in the year 686, the political geography of England had reached a stage from which it was not to vary in any marked degree for some 200 years. Indeed, there was nothing accomplished in the way of further encroachment on the Celt after 686, save Ine's and Cuthred's extension of Wessex into the valleys of the Tone and the Exe, and Offa's slight expansion of the Mercian frontier beyond the Severn, marked by his famous dyke. The conquests of the Northumbrian kings in Cumbria were ephemeral; what Oswio won was lost after the death of Ecgfrith. The "Bretwaldas."