Articles Proper Nouns – Why Use Definite Article Before ‘Jesus’ in ‘The Jesus Who Said’?

The article goes with language, so the following work as noun phrases:

English

the English language

The following doesn't usually work as a noun phrase referring to the English language. It would more likely be interpreted as referring to the English people:

＊the English

Take a look at the following example sentences:

1a. I speak English.

1b. ？I speak the English language.

1c. ＊I speak the English.

2a. English is a beautiful thing.

2b. The English language is a beautiful thing.

2c. ＊The English is a beautiful thing.

Examples 1c is wrong. Example 2c is wrong in most situations. Example 1b sounds strange; we usually only say "the English language" when speaking about the language in the abstract or as a whole. Saying "English" always works, though it doesn't always sound as nice:

3a. By some estimates, there are over a million words in the English language.
3b. By some estimates, there are over a million words in English.

Both examples are acceptable, but example 3a sounds better.

Of course, there are other situations where you'd use an article with bare English, such as in the phrase the English of Shakespeare, but you can do that with any proper noun (see this answer). And if you're using English language as a modifier, it doesn't need an article because it's not functioning as a noun. In the following example, English language is inserted into the noun phrase a Q&A site as a modifier:

4. Stack Exchange is an English language Q&A site.

The article an belongs to site, not to English, language, or Q&A.

＊ means I think this utterance is unacceptable.
？ means I think this utterance is questionable, but not as bad as those marked with ＊.

PROPER NOUNS

• Use the with names of geographical areas, rivers, mountain ranges, groups of islands, canals, and oceans. Example: Hiking across the Rocky Mountains would be difficult.

• Use the with countries that have plural names Example: I have never been to the Netherlands.

• Use the with Organizations, government, committees, parties, associations, foundations, clubs Example: the Congress of the United States, the United Nations (the UN).

• Use the with countries that include the words "republic", "kingdom", or "states" in their names. Example: She is visiting the United States.

• Use the with newspaper names. Example: She works for the New York Times.

• Use the with the names of famous buildings, works of art, museums, or monuments. Example: We went to the Louvre and saw the Mona Lisa.

• Use the with the names of hotels & restaurants, unless these are named after a person. Example: They are staying at the Hilton on 6th street.

• Use the with the names of families, but not with the names of individuals. Example: We're having dinner with the Smiths tonight.

WHEN NOT TO USE "THE"

• Do not use the with names of countries (except for the special cases above). Example: He's just returned from Zimbabwe.
• Do not use the with names of shops Example: I'll get the card at Smith's.

• Do not use the with uncountable nouns Example: Milk is often added to tea in England.

• Do not use the with the names of individual mountains, lakes and islands Example: Mount McKinley is the highest mountain in Alaska.

• Do not use the with most names of towns, streets, stations and airports Example: She lives in Florence.

For your sentences:
These stuffs are imported from the United States. (countries with states in their names)
History of Britain can date back to The Medieval. But we write: History of Britain can date back to Medieval Times.
A question is asked on ELL.SE.