Soemil was an early Northumbrian king who ‘separated the Sea-land (Deira) from the Hill-Country (Bernicia)’ and whose name is of obscure meaning.
Amongst the tattered threads of the remaining records of British rulers, we have a Samuel, son of Pabo ‘Pillar of Britain’, located south of the Pennines.
I find it hard to believe this Soemil and this Samuel are not somehow (not necessarily directly) related and that the Soemil of the English record was a British king called Samuel hoovered up into later traditions to give it antiquity and legitimacy.
Notes.
1) The early and definitely English Bernician king Ida has a name curiously similar to the Pictish (that is, northern British?) name Uuid (earlier form ‘Veda’), possibly in origin a cultic name (‘seer’) related to early Irish names such as Fedelmid (m) and Fedelm (f).
2) An ancestor of Ida was ‘Ingwi’, an interesting retention of the traditions of the Ingaevones.