Alba
Alba had many competing rulers in 878:- King Áed
- King Giric (Son of Fortune)
- King Eochaid
Gwynedd
The ruler of Gwynedd was King Anarawd ap Rhodri.
Mercia
The ruler of Mercia was King Ceolwulf II, who had ruled since 874 and would continue to do so until 883.
Northumbria
The ruler of Northumbria was King Ecgberht II, who had ruled since 875 and would continue to do so until 895.
Strathclyde
The ruler of Strathclyde at this time was likely to have been King Dyfnwal.
Wessex
The ruler of Wessex was King Ælfræd (Alfred the Great), who had ruled since 871 and would continue to do so until 899.