Any name can contain a space. For example "Ana Maria" is a common first name which contains a space. On official documents, generally a name will be separated into a given name and surname. In this case "<A> <B C>" and "<A B> C" are considered separate names.

Source: I have a space in my name and some of my different identity documents have the name as "<A> <B C>" or "<A B> C", which causes all sorts of administrative problems.

Leonardo da Vinci is another famous example of a last name with two words in it. It's very common in romance languages. Plus, lots of people in the American south just flat out have two first names or two middle names.

Da Vinci isn't his last name, just like Jesus's last name isn't "of Nazareth" and Cato the Elder's last name isn't "the Elder"

Last names in many places evolved from that same need to disambiguate between people though. Attach some marker of connection to a place (common in Finland, e.g. Joensuu meaning "mouth of river"), profession (common in Germany and UK, e.g. Müller, Cooper, meaning mill worker and barrelmaker), lineage (common in Iceland, e.g. Grímsson meaning "son of Grímur"), or some other culturally relevant characteristic.

Nowadays the meanings of our last names have largely disappeared, so you have countless Coopers who have never touched a barrel in their lives, whose children will be called Cooper also, despite that. I think it's a little sad that so much of what people call us is semantically equivalent to a random UUID with tons of namespace collision. With that in mind, I'd say "da Vinci" is more a last name than most of us have.

Having a name with "of Region/city/former kingdom/..." is often their last name. Unless you want to claim that these people do not have a last name.

I can understand that in some cultures this might seem weird or antiquated but here in Germany these names are reality. Sometimes people with such names are descendents of royalty and sometimes someones last name "from family-name" is thier last name and happens to historically correspond to one of germany's state names or city names or just a little town.

One a side note: In Germany in 1919-1920 royalty was no longer a legal aspect that changed how laws applied to you[1]. When that happened titles that were reserved for ruling functions (king, grand duke) were removed and all other titles were moved to be part of the persons name (such as prince etc.) and could not be decreed on anyone new. These titles still exist in Germany but are simply naming "conventions" in a formerly royal family.

[1] https://de.wikipedia.org/wiki/Adelsrecht

[edit] In Leonardo's case perhaps not but still i wish to elaborate a litte on the situation here.

When speaking about him in English, why do we say "Da Vinci" instead of "of Vinci"?

We'd probably have to say Leonard of (Anglicized form of 'Vinci') for maximum consistency in that case. Lenny Vince for short.

c'est la vie /s

Seriously, though, it just feels apropos.

Leonardo da Vinci's name was Leonardo, and "da Vinci" refers to Leonardo's birthplace.

Correct: his full name as given was "Lionardo di ser Piero da Vinci," meaning more or less Piero's son Lionardo from Vinci. Deriving a childs name from their lineage was incredibly common.

Lineage names still exist in the West, but lineage naming is not as common. See Ken Thompson, or even Johnson & Johnson's vaccine!

Documents aside, do you consider <B> to be a given name (parent came up with it) or a surname (parent already had it)? If given, do you consider it optional (i.e., middle rather than first)? Sorry in advance for any shortsighted assumptions about the possibilities here!

Relevant and almost as horrifying as the address one: https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-...

While we're on the topic...

A UK passport has a "surname" field and a "given names" field. But a recent UK birth certificate has a single name field in which the "surname" part is distinguished by being written in capitals, so "Peter James ADAM SMITH" would have a surname consisting of two words. But what if a word consists of a single letter? For example, some Irish surnames look like "O Briain", and I think there is a Vietnamese name that consists of a single vowel, so presumably you can't always tell from the birth certificate which part is the surname.

In Italy there is First Name, Other Names, and Family Name on the birth certificate. All fields can contain spaces (as well as hyphens, apostrophes, and some other diacritics).

The legal name however consists of First and Family names only, without the other names. Therefore many people have two names in the First Name field, usually separated by a space. The disadvantage is that in all official forms they have to spell out all the first name(s), no omissions or abbreviations are generally admitted.

One nice side-effect of this is that you can have a bit of fun with the Other Names since they're "unofficial". If the child wants to use those names later, they can, if they don't, they can pretend they don't exist. Some friends of ours put "Danger" in their kid's "other names", for example.

Multiple middle names are common in Sweden.

The Swedish situation is... confusing. :-) There are first names ("förnamn"), possibly more than one. The one in daily use — not necessarily the first one! — is called "tilltalsnamn" (something like "addressing name"), and is traditionally marked in official paperwork by underlining or with an asterisk. (You know someone has not done their homework when you get junk mail that starts with "Dear <Wrongname>!) Then there used to be middle names ("mellannamn"), which was something put between the first and last names. These were typically used e.g. by people who wanted to have both their own and their spouse's name. These are no longer issued, though those who have them can keep them. Instead, you can now have a double last name, which used to be impossible. (People have sported "double-barrelled surnames" for ages, but they have not, as far as I can understand, been officially recognised, but functioned more like "stage names").

Not really, it is quite similar to sourthern countries.

Typical Portuguese names have around 5 names, two first names and three surnames from both parents.

In fact your description fits quite well how they are used in Portugal, plus a few other nuances.

The confusing bit is that the rules about middle names and double surnames have changed at least twice in... my lifetime, which is becoming much longer than I care to think about. :-) I didn't do a very good job of conveying that in my comment.

Is "middle name" a separate concept in Sweden? In Germany, there is no middle name, but people can have more than one first name.

So, Heinrich August Schmidt has a last name / family name (Schmidt) and two first names / given names.

Small nitpick, if you are* in Germany but have an e.g. Spanish name (e.h. Hector Garcia Gonzalez) then... that's 2 surnames without a dash. I have no idea what happens if you marry or have children, but your example is just the -most basic- version.

*"you are" meaning you'd be a German citizen with a German passport.

> I have no idea what happens if you marry or have children

When you marry, you get to define what is going to be the family name and then children born from that marriage get to be registered with that family name.

In the case of foreign-born people, they can keep the naming rules from their original country. In the case of the marriage between foreigners from two different countries, you have to choose which rules are you going to follow, but the family name stays fixed.

To us (Brazilian marrying a Greek) it was a very interesting process. I have two last family names, and Greek names are gender-conjugated (i.e, the last name changes whether you are a boy or a girl). It the end the simplest thing to do was to just keep only one my last family names.

My German children have a last name with a space in it (ie. 2 last names, but not with a dash). This also shows up in their German passport.

This is possible because you can make a “name declaration” where you choose to apply the naming law of another EU country.

There are two different definitions of "middle name". Almost every American middle name is a given name or a surname used in the middle.

Had a set of twins in my town whose parents were Greek and they had two middle names and I was so fascinated about it as a kid I'll never forget.

Is it that rare? I have two middle names (William Howard) and I never thought much of it. As a kid, I was more amused by a friend of my sister's who had a quadruple-barrelled surname...

George Herbert Walker Bush wasn’t a familiar name in your youth?

Is there a limit that a person can have only one middle name?

In practice, yes.

I have two middle names; most financial service providers decline to recognise my second middle-name. Same goes for the taxman and my pension provider. It seems that a "full name" is no longer a canonical identifier for a person, just really a kind of nickname; the canonical identifier is now an account-number, employee-ID or whatever.

Thanks to marriage, names were non-canonical before the computer was even invented.

And thanks to people moving house, or even changing profession, or acquiring some defining trait or accomplishment. With most people being undocumented throughout history, names could be much more fluid, like the way a person's "nickname" may change many times with or without consent.

No. There is not limit. That can by proven by seeing people with multiple middle names or by naming your child with multiple middle names. How could there possibly be a limit? Even with the case where systems can not store or recognize the length of such a name, the middle names themselves are not limited. People's names are not entries in a compiler's symbol table.

My son has two middle names (one for each grandfather), but he's still very much a minor and so not in very many "systems" yet.

(Although probably a lot more than I know about.)