Alcuin (AD735-804) turns out to be the most important Anglo-Saxon (specifically, Northumbrian) you’ve never heard of.
A swerve in Western culture
He was a crucial educator, preserver and sharer of knowledge at a time when a rich tradition of learning was in danger of being entirely wiped out in Britain (thanks to the Vikings) and in wider western Europe:
According to Mary Garrison:
Because the word “renaissance” has been so well domesticated in the English language it’s easy to think that every renaissance was inevitable. But before Alcuin classical learning was hanging by a thread. Alcuin – not the rediscovery of Lucretius in early modern times – is the true swerve in Western culture, because if Alcuin hadn’t rescued the harvest of Northumbrian learning from York, this capacious program of studies, and brought it to the content and brought the books to the continent before the Viking devastation of the British Isles, I think the literary and cultural and intellectual history of the West would look complete different.
…In Malcolm Gladwell’s terms he was a maven, a connector and a persuader. He had this massive knowledge that he was able to make attractive and spread to people. If you make a sort of geneology of his students and their students it’s like a sun shining across Europe. And what one of Charlemagne’s biographers said: “There was not a single great abbot or bishop of the following generation who was not taught by Alcuin.” So this is getting back to the idea that one person made an astonishing difference at a crucial moment in history.
A copperplated alibi
He was also the inventor of – more or less – the version of the alphabet you’re reading right now, Carolingian miniscule:

Check out the episode from the BBC here.
Highly recommend.