"Alexander" was an incredibly common name in the Greek world. Even within his own family tree, he was technically Alexander III of Macedon. Using "The Great" was a practical necessity for historians to distinguish him from his father’s predecessors and the dozens of other Alexanders running around the Mediterranean. Plus his scale of impact was absurd! Charlemagne literally means “Charles the Great” because there were many Charleses. Finally, while we usually think of Julius Caesar, "Caesar" became a title used by every Roman Emperor for centuries. It eventually evolved into "Kaiser" and "Tsar". If you just say "Caesar" in a room full of Roman history buffs they actually will ask you to disambiguate which one you mean

There’s only 1 Caesar

Not necessarily. I originally thought the phrase "Render unto Caesar what is Caesar's" from the Bible referred to Julius Caesar, but apparently it refers to Tiberius.

Though in modern times "Caesar" almost ubiquitously is referencing Julius

Fun fact: there was actually zero Charlesmagnes.

The guy was called Charles le Magne (French for Charles the Great) and some barely literate idiot who had somehow* got the translator job in spite of clearly not being anywhere near fluent in French made up a stupid new word born of ignorance that the English speaking world has been using ever since.

*I'm guessing he was the failson of the groom of the stool or something like that.

Charlemagne is in the same boat, it means Charles the Great

Among Greeks, if you say Alexandros (or Philip for that matter) then people will know who you are talking about. But basically, those names are still in use. Caesar became the word for leaders rather than a name, and it's relatively rare as a first name.

Charlemagne is actually Charles le magne which means Charles the Great. If you called him "King Charles" you'd need to be much more specific.

I can't speak for Attila, because I don't know if the name is popular in any particular cultures. Certainly in the USA, the Hun king is the most famous Attila.

Slim Shady is an interesting example, because its's basically branding for Marshall Mathers aka Eminem. One of his first widespread hits was a song essentially saying that he's the only real Slim Shady, and anyone else using that nickname is a copycat poser.

Alexander is a common name, but it depends on context, if you say "at the time Alexander conquered X" most people would understand, but if you say "Alexander was here" you might be talking about a work college.

There's not only one Caesar, while you probably beat Julius Caesar, Augustus, Tiberius and others were also "Caesar", and you might referring to any of them. For example, "give to Caesar what is Caesar’s" does not refer to the same Caesar you probably meant.

Slim shady is a made up name and it's way more specific than the .

Charlemagne is short for Charles Magnus, or in English Charles the great, so that's exactly the same.

Attila is a very unique name, I've never met nor heard about any other Attila so the name is disambiguation enough, but it's likely that if that is a common name in some country they have an extra qualifier to it, I've heard Attila the Hun, but there might be others.

There's nothing special, if a name is common you need disambiguation, if a name is overly specific you don't, same reason why we have last names, "I met with John the other day", "which John?", "The Smith", "Ah yeah, John Smith, not John the son of Richard", "No, I haven't seen John Richardson in a few weeks".

Caesar, or Charlemagne or Attila.

Well, those are fairly uniquely-identifiable names in the scheme of things. "Caesar" isn't just the guy at your local pizzeria, but THE Caesar of Caesars. "Charlemagne" is a combination of the common name "Charles" and <"great"> as with Alexander. "Attila" is a rarer name, already with a certain stigma, so quite unique in that sense.

"Alex" / "Alexander" is still a pretty common name today, so it makes some sense that there'd be a qualifier. Not unlike with Peter the Great , Catherine the Great, etc...

While there is only one Gaius Julius Caesar, his lastname has been used as title by various successors.

Slim Shady is a self invented stage name so there is not really a point in anyone adopting it as their own unless they are comfortable being called a copycat all the time.

Charlemagne actually is short for the French version of Charles the Great so it is a title name combination just as Alexander the Great.

Atilla probably sounds unique to you because it's an uncommon name in the west.

You don't want to get him mixed up with Alexander the Just Kind of OK at Things, do you?

I know like 5 dudes called Cesar.

"The Great" is a moniker given to certain rulers. England has only one. List of people known as the Great - https://en.wikipedia.org/wiki/List_of_people_known_as_the_Great

All the other Alexanders are just imitating

!look, there were already great answers, so there was room for a joke one!<

There’s only 1 Caesar

Julius or Augustus? Or Edward Swallow, Ave, trve to Caesar!

Caesar is actually a title, and where the German word Kaiser and the Russian word Czar came from.

Slim Shady is a rap name, it's probably copyrighted tbh.

Charlamagne the God or Charlemagne the King/Emporer?

I'd say it's because Alexander is still such a very common name.

“Charlemagne” literally means “Charles the Great”.

In my experience, in context people often do drop the "the Great" and just say Alexander.

No, it's because he conquered the known world, and he left a lasting influence/political structure behind him as he went.

there's several caesars, slim shady nobody else has that name, Charlemagne is French for Charles the Great, and Attila was antiwestern so they wouldn't name him "great"

Pretty sure his friends call him Alexander of Macedonia.

disambiguate

quite a meaningless idea.

It was meant to praise him, not because of any kind of neccessity.