Article the with characters' names

Why do we use article 'the' with names of fairytale characters? For example, Peg the Hen, Fuzzy the Hamster, Cheeky the parakeet?

Solution 1:

It is no mystery. ‘The’ is used for specification. So I ask “How much is that doggy in the window?”. You ask “Which one?”. I answer “The one with the waggly tail.” (i.e. the doggywith thewaggly tail).

Someone in a mediaeval village might tell you "That’s Jack the miller.". Eventually it turned into Jack Miller!. Down through history, famous people have be given adjectival titles: Pompey the Great, Ivan the Terrible, Ethelred the unready, Jack the Ripper, Elizabeth the second. Named fairytale and fiction figures are just an extension of that: the Cheshire cat, the severn dwarfs, the beast, Winnie the Pooh.

I am not aware of a technical name for this usage. It is, in any case far from universal, as Kate Bunting points out in a comment.

This has not always been so and is not so in all languages. So Pompey the Great did not have a definite article in the original Latin, which does not have a definite article. He was just called Pompeius Magnus (or, more strictly, POMPEIVS MAGNVS); and the Anglo-Saxon king, Ethelred had no definite article, either: he was Aethelred Unraed. David in his comment has pointed out how the use of a specifying definite article of this kind is detectable in Norman French names: Legrand, Leblanc, etc... I am not aware that such a use of the article is met in modern French writing.

If we wanted a name for this usage, we might call it the definite article of specification. But why add to the list of technical terms, already sufficiently long?