This was both one of the most turbulent and peaceful periods in the history of Cymru. During the reigns of Rhodri Mawr and Hywel Dda, there were wars with the Anglo-Saxons and the Vikings. This was also a time when Cymru became a unified country with fewer internal disagreements.
The greatest threat came from the Saeson (Anglo-Saxons) in the east who had driven west with relentless determination and were stopped at the Wye Valley. Offa, a Saxon king, built his dyke to keep the Cymry from regaining their hold on territory in what was becoming England.
The Cymry were never expelled from their country (now known as England and Scotland).
At this time, dialects of Cymraeg were still spoken from Caeredin (Edinburgh) to St. Ives as well as in Brittany (Llydaw).