This article is about the particular significance of the century 801–900 to Wales and its people.
830
878
893
- Spring – Battle of Buttington,[2] a victory for a joint Anglo-Saxon and Welsh force against the Vikings; the Buttington Oak, planted about this time, perhaps to commemorate the event, falls in 2018
- Autumn – Danish Vikings are forced from Chester into Wales.
854
808
809
- Elfodd, bishop of Gwynedd,[5] who persuaded the Welsh church to adopt the Roman method of determining the date of Easter
844
855
871
- Gwgon, king of Ceredigion and Ystrad Tywi[6]
878