Does "Magna Carta" require an article?

The funny thing about the definite article is that it is used differently in America (AmE) than in England (BrE). In general, I believe BrE has a tendency to drop it, where AmE has a tendency to insert it.

The most famous example is the word Hospital. In the US, a person goes "to the hospital", while in the UK one goes "to hospital". I'm gathering that "Magna Carta" is also in this boat.

To my American eyes, using it without "the" just looks wrong. I'd be tempted to think either the writer is referring to some other "great charter" (that's what the Latin translates to), or that they are being disrespectful.

So basically, I think you'll have to figure out which group is your primary audience, and accept that you are going to tick off the other. :-)

First a baldly stated answer:

In AmE, it is 'the Magna Carta', spoken or written, but headlines may drop the article as they usually do.

Now commentary: I wondered what the ballyhoo here was about (the) Magna Carta until I heard on the news today about it's 800th anniversary... from the BBC... in which the announcer talked about 'Magna Carta'. And, I, as an AmE speaker, thought that was jarring. To my ears it definitely needs an article.

That said, this shows the difficulty in making pronouncements. Maybe the announcer (or copy editor) is weird. Maybe I'm weird, maybe the professor in the interview is weird, maybe you're weird (weird = out of the ordinary). Maybe the corpora are skewed/selected weird/use headlines mostly, etc. etc. etc. And maybe 'ordinary' is very context dependent.

And it seems like all the data that's been gathered so far (Google NGrams/COCA/BNC) is inconsistent. So all I have to go on is the dreaded introspection.

Since "Magna Carta" is a Latin name and Latin would not need the use of an article then it is technically improper to use the definite article with it.

However, both seem to be acceptable in normal usage.

Source: http://www.oed.com/view/Entry/112237?redirectedFrom=Magna+Carta

(may need a subscription so here is the relevant text pasted in)

"Usu. without article."

My understanding is that the use of "Magna Carta" is a historical convention. However, like most historical conventions, it is being forgotten and the default treatment is being applied, making it "the Magna Carta".

I am not sure of the rationale of that convention, but it is notable that "Magna Carta" is a name that only attached to the document(s) much later, and in any event the original (1215) Magna Carta was swiftly set aside by the Pope and the Magna Carta which had legal force (and different wording) did not exist until 1255 when Henry III was old enough to sign it. So perhaps calling it "the" Magna Carta when you're talking about a legal document issued and reissued in many copies and versions over 40-odd years makes no sense. It's not a single document ("the MC"), it's not part of a group ("a MC"), it's just a class of things called Magna Carta.