More precisely: the first letter of a name is always capitalised.
So in "Hans de Zwart", the 'H' is the first letter, and therefore capitalised. But in "De Zwart", the 'D' is the first letter, and therefore capitalised, even if it normally wouldn't be.
There might be an exception to that if that letter is not part of a whole word. "De" is a word, but I once knew a guy whose last name was 't Zet. The "'t" is not a word (it's short for "het", the neutral version of "the", whereas "de" is gendered[0]), so probably wouldn't be capitalised[1]. Now imagine 200 countries and languages with exceptions like that and imagine having to write software to handle all of that correctly. This stuff was never a problem before the internet, but I expect the next century is going to see a lot of simplifications in language.
[0] Yeah, in Dutch, there are two articles: "de" which is gendered, and "het" which isn't. Compare to French "le" and "la", which are both gendered, one male and one female, and there's no neural article. In Dutch there is, but the gendered article doesn't care whether it's male or female; it works for both and doesn't actually care about gender, just that it's there. So it's gendered in a neutral way. Wrap your head around that.
[1] This is also true at the start of a sentence: always capitalised, except when it's not a complete word. If you start a sentence with 's avonds ("in the evening), you capitalise the 'A', not the 's', which is actually the last letter of the archaic possessive 'des'.
> [0] Yeah, in Dutch, there are two articles: "de" which is gendered, and "het" which isn't. Compare to French "le" and "la", which are both gendered, one male and one female, and there's no neural article. In Dutch there is, but the gendered article doesn't care whether it's male or female; it works for both and doesn't actually care about gender, just that it's there. So it's gendered in a neutral way. Wrap your head around that.
That's a curious way to present it. "het" is gendered, it corresponds to the neuter gender. There is nothing neutral about it, that's just a (bad) name. In Russian for example, they call it the middle gender. Dutch nouns take one of two genders (three in some Belgian dialects), just like in French.
Both Latin and Proto-Germanic had three genders, which correspond to what we would now call male, female and neuter. Over the span of centuries Latin merged male and neuter into one, leaving French with male/female, whereas in the Germanic languages usually male and female merged into a common gender, leaving common/neuter. But apart from that, it's exactly the same phenomenon.
Since we're bringing up fun facts about Dutch capitalisation, when the first two letters are "IJ", which pronounced as a single letter (a vowel) in Dutch, then both are capitalised.
There are (a lot of) people who consider the 'ij' to be a single letter. When asked whether that means Dutch has 27 letters in the alphabet or the 'y' is not a Dutch letter, the discussion becomes very confused. Best explanation is probably that the 'ij' is a letter that's not in the alphabet, or it is, but shares the 25th spot in the alphabet with the 'y'. But it is still a different letter, because "symbool" and "royaal" are also valid Dutch words. The situation isn't helped by the fact that some names and words that currently contain an 'ij' used to contain an 'y'.
(Personally I think it's two letters, but there are very serious sources, including a major encyclopedia as well as primary schools, that disagree. In games and puzzles it's also usually considered to be a single letter.)
> This article was written by Reinier Kist and originally appeared in Dutch in NRC on August 3rd, 2020. It was translated into English by Hans de Zwart.
In the original source: https://archive.is/g6H0F it is also "De Zwart" when without the first name, and I would reasonably trust NRC to get it right.
