Does "Magna Carta" require an article?

I have seen (the) Magna Carta referred to both with and without an article, a distinction that doesn't seem to have any relation to nationality (i.e. I've seen British sources and American sources both use and omit the article).

"Stop Revering Magna Carta"— The New York Times

Through Coke’s treatises, Magna Carta traveled across the Atlantic. William Penn published an edition in 1687, and in the 17th century several colonies enacted Magna Carta as part of their law. With the Stamp Act of 1765, the imagery of a tyrannical government impinging on ancient rights proved useful to both John Adams and Benjamin Franklin, who invoked different provisions of Magna Carta in calling for repeal. The founding fathers thought they were drawing on the document in drafting the Constitution, for example, in the clause “due process of law” — though that phrase was added to Magna Carta in English law only in the 14th century.

The Magna Carta enshrined our liberties - now we must fight for them again — The Guardian

It’s because of the Magna Carta that, in 2003, 3 million of us were able to come together to protest against the Iraq war. It’s the Magna Carta that means we can legally fight cases where a severely disabled person is confined to a single room because her local council has failed to provide suitable housing. And, ironically, it’s the Magna Carta that has ultimately allowed us to vote in a government that seems hell bent on destroying it.

Is one usage preferred or more acceptable? Does the Latin nature of the phrase "Magna Carta" remove the normal need to attach an article?

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."

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.

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.

The OED says of "Magna Carta": "Usually without article."

It has two definitions - it can refer to the "charter of English personal and political liberty", and in this sense, none of the OED's nine citations have the definite article (though one of them has the determiner "his") - or it can refer to "any similar document", and in this sense, some of them do have the article.

Some proper nouns are preceded by an article and others aren't (and some common names such as "parliament" gain a capital and often drop their article when referring to the actions of the British Parliament: "Parliament has decided ..."). The other "great charters" are all referred to with the definite article. So it is at least possible that the fact that "Carta" isn't an English word, and the fact that "Magna Carta" is a proper noun made up entirely of foreign words, may have discouraged the use of "the" historically. It is difficult to think of another great historical document or charter that is named in English without using a definite article, but it is also difficult to think of another one with a comparable name.