According to my crumbling book of English history, Richard the Lionheart thrust England into the international stage. Before him, England was just a curious outlier in European and middle eastern affairs; an upstart kingdom.
To amend my post above (not sure what to “excuse monarchs” means.) My private citizen candidate is Sir Francis Drake (during his pirate days.)
Richard the Lionheart was about as English as Charles de Gaulle.
Of course in 1157, no one else could, either. Well, until 1938. 
Yeah, but David Hasselhoff was definitely single-handedly responsible for bringing down the Berlin Wall. He was, I heard him say so!
Would the Wycliffe bible have been widely known or influential abroad in its day? (if that counts as ‘english’ as we know it?)
Aside from those already mentioned, the average Bavarian, at least, would likely know something about Sir Benjamin Thompson, Count Rumford. Born in Woburn, Massachusetts, from 1785 he was one of the top advisors to the Prince-Elector of Bavaria, reorganizing the army, starting workhouses for the poor, and built a large public park in Munich. Also, his name is on cans of baking powder.
I’d say, the answer has to be Shakespeare. He was hugely popular in Germany, especially in the 18th century and later. Being able to read Shakespeare would have been an incentive to learn English in the first place at a time when French or Italian were much more important (living) languages.
I think the answer is Bede, then. He was known to be English, or at least Anglian, and thus presumed to speak English.
For a writer whose English was read by foreigners, it’s going to be someone in the late Middle or Early Modern English period. Chaucer is a good suggestion for someone who might have been read outside of England, and perhaps Spenser. Shakespeare, too, but I suspect there’s a little lag time with all of these, and I don’t know how many decades / centuries before they caught on outside of England.
OK, that made me laugh! Happy 4th!
Which is pretty much exactly what the other fellow’s cite said. I guess he didn’t read it.
[moderator note]
As you noted, this is the GQ forum. Tone it down and back off the personal attacks.
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