Alt Clut
The ruler of Alt Clut during this time was either King Dumnagual map Riderch (Dumnagaul IV) or King Arthgal map Dumnagual, the exact year of the succession is unknown.
Dál Riata
The ruler of Dál Riata at this time was likely to have been King Domnall mac Caustantín.
Dumnonia
The ruler of Dumnonia during this time was either King Hernam ap Oswallt or King Hopkin ap Hernam, the exact year of the succession is unknown.
Gwynedd
The ruler of Gwynedd was King Hywel ap Rhodri Molwynog, who had ruled since 814 and would continue to do so until 825.
Mercia
The ruler of Mercia was King Cœnwulf, who had ruled since 796 and would continue to do so until 821.
Northumbria
The ruler of Northumbria was King Eanræd, who had ruled since 810 and would continue to do so until 841.
Fortriu
The ruler of Fortriu was King Caustantin, who had ruled since 789 and would continue to do so until 820.
Wessex
The ruler of Wessex was King Ecgberht, who had ruled since 802 and would continue to do so until 839.