I can only answer with qualifications. I would be sorely tempted to begin any list of kings of England with Offa, because he reduced several neighbouring kingdoms to the status of earldoms and effectively ruled almost all the territory of what is now England one way or another. He was a stronger figure than Egbert, the Kentish graft onto the West Saxon family tree who often heads king-lists. Alfred the Great was king of the English south and west of the Danelaw; his grandson Athelstan is regarded as first king of England by the Royal Historical Society's Handbook of British Chronology, and consequently by the Oxford Dictionary of National Biography, though he never used that title, preferring 'king of the English'. So, I'll go for Athelstan, but it's by no means cut and dried. I think the first monarch actually to call himself 'king of England' (rex Angliae) was either John or Henry III (I suspect the latter) in the thirteenth century, imitating the French kings who had shifted under Philip Augustus from 'rex Francorum' (king of the Franks) to 'rex Franciae' (king of France).
IIRC...
editemperor's answer reminds me that it was Edred (Athelstan's half-brother) who finally snuffed out the Northumbrian kingdom by elimiating Erik Bloodaxe, so he does have a claim, though there had been kings of the West Saxon line recognised in York/Jorvik before this, and the earls of Northumbria ruling north of the Tees generally seem to have acknowledged West Saxon overlordship as a bulwark against York, though not consistently.
And don't forget the claims of Edgar, who put himself through an elaborate coronation ceremony in 973, though that might have been more of a claim to be king of Britain as opposed to the English. Lots of overlapping identities back then, as now.
I think some of the thirteenth-century monarchs used 'rex Scotiae' on occasion, almost certainly definitely King John [Balliol] though his title to the throne rested on a distinct basis to his predecessors and successors. It's all in A.A.M. Duncan, The Kingdom of the Scots, which is well worth reading, though very historically contentious.
no subject
Date: 2008-09-03 10:58 am (UTC)IIRC...
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And don't forget the claims of Edgar, who put himself through an elaborate coronation ceremony in 973, though that might have been more of a claim to be king of Britain as opposed to the English. Lots of overlapping identities back then, as now.
no subject
Date: 2008-09-03 08:08 pm (UTC)no subject
Date: 2008-09-04 09:27 am (UTC)Like the Scots monarchs, who were 'Kings of Scots' right to the end of the song (though people persistently get this wrong).
no subject
Date: 2008-09-04 09:33 am (UTC)