(716-755), "ravaged the land of the Northumbrians," and made Wessex
acknowledge his supremacy. By this time all the minor kingdoms had
practically become subject to the three great powers, though still
retaining their native princes: and Wessex, Mercia, and Northumbria
shared between them, as suzerains, the whole of Teutonic Britain. The
meagre annals of the Chronicle, upon which alone (with the Charters and
Latin writers of later date) we rest after the death of Bæda, show us a
chaotic list of wars and battles between these three great powers
themselves, or between them and their vassals, or with the Welsh and
Devonians. Æthelbald was succeeded, after a short interval, by Offa,
whose reign of nearly forty years (758-796), is the first settled period
in English history. Offa ruled over the subject princes with rigour, and
seems to have made his power really felt. He drove the Prince of Powys
from Shrewsbury, and carried his ravages into the heart of Wales. He
conquered the land between the Severn and the Wye, and his dyke from
the Dee to the Severn, and the Wye, marked the new limits of the Welsh
and English borders; while his laws codified the customs of Mercia, as
those of Æthelberht and Ine had done with the customs of Kent and
Wessex. He set up for awhile an archbishopric at Lichfield, which seems
to mark his determination to erect Mercia into a sovereign power. He
also founded the great monastery of St. Alban's, and is said to have
established the English college at Rome, though another account
attributes it to Ine, the West Saxon. East Anglia, Kent, Essex, and
Sussex all acknowledged his supremacy. Karl the Great was then reviving
the Roman Empire in its Germanic form, and Offa ventured to correspond
with the Frank emperor as an equal. The possession of London, now a
Mercian city, gave Offa an interest in continental affairs; and the
growth of trade is marked by the fact that when a quarrel arose between
them, they formally closed the ports of their respective kingdoms
against each other's subjects.