I promised you to talk about it, back when I made my post about caloric magic: unfortunately I lost the article I wanted to reblog as a reference (it is somewhere drowned in my likes). I will still do the post, but quite late and succinct as a result: I want to speak about how bizarre the use of "True Names" is today.
Because if you go onto the Internet, if you check "True Names magic", "Do not share your True Name", "True Names have power", all you get is... Fairies. Fairies, faeries, fae, fair folk, elves, whatever. The Internet today not only proclaims but runs with the idea that a core part of fairy lore, of fairy fiction, of fairy tradition, relies on the existence of a "True Name" that is a powerful thing the fairies protect at all costs, because whoever has them can enslave them. It is everywhere - Mercy Thompson, Modern Faerie Tale, Dresden Files, Shadowhunters, World of Darkness, Spinning Silver...
And... this is utterly, entirely, completely false. Entertaining, charming, a whole aesthetic sure, a freshly-made tradition, but artificial, out of nowhere and heavily misleading to the point of nearing misinformation.
Mind you, it does not come from "nowhere" per se. There is ONE recurring fairy-story that did give credit to the idea that "True Names" were connected with the Fair Folk/Little Folk: the brothers Grimm' Rumplestiltskin, where to defeat the titular antagonist the protagonist must guess his name... However this is A) an exception to the rule as you will find no other popular stories showing fairies relying on their name ; and B) completely missing the point. When you check the many variations, from country to country and era to era, of the "Rumplestiltskin" fairytale-type (type number 500 per the International Classification), you notice that what all the names to guess have in common is weirdness, bizareness, ridiculousness. The "guessing of the name" trial relies not on on the "importance" of the true name, but on the fact the name is just so convoluted and hard to pronounce nobody could guess it.
Fairies in folklore and legend do NOT rely on "True Names" as we understand it today... So where does this whole thing came from?
[EDIT: Mind you, there are, here and there, some little stories about supernatural beings able to be vanquished when their name is spoken aloud, I am not saying it does not exist... But I am saying it is quite minor and not a core nor prominent part of "fairy lore"]
Well, the answer is fantasy. In terms of "magic of True Names", it was the fantasy genre that popularized it. While foundational works like Tolkien's books rely heavily on the importance and multiplicity of names, there's no "True Name" power as we understand it ; similarly its mythical sources do not rely on this either. Yes the Kalevala relies on magic being performed by knowing the "true essence and origin" of the things, but it has nothing to do with "names" at all - to have power over something, you need to be able (for example) to sing how it came to be and how it was conceived. It is knowing the "true tale" of something that is important, not a "true name". [EDIT: Okay, the dwarves of Tolkien do have "true names" they keep secret to their graves and yes names do have significance and power in Tolkien's Legendarium, but it doesn't fit what we understand as "True Names" today]
True Names started in fantasy with... Le Guin's Earthsea. She was the one who first brought the concept that magic uses and relies on True Name ; she was the one who built a world where people kept secret their True Names and went by nicknames or titles ; she was the one who wrote about how you could bind someone using their True Name. And it was from "Earthsea" onward that this concept was used and reused in fantasy - for example in Glenn Cook's "The Black Company" where speaking a sorcerer's True Name means the end of their magic - and the idea that the "True Name" rule only works for magic-users is apparently also found in Niven's "The Magic Goes Away"?
In fact, in fantasy the "Law of Names" was mainly focused as being a purely magical thing. Either it was how wizards and witches worked their magic (like in "The Forgotten Beasts of Held", "Dragonsbane", "Young Wizards" or the "Inheritance Cycle"), either it is a threat to the sorcerer itself, see above. This is very likely because of how Earthsea focuses on the wizards and mages. Similarly sometimes the "True Name" was expanded to dragons, and I suspect it is because the most iconic use of a True Name in Earthsea was against a dragon... And from sorcerers and dragons, the trope slowly slipped into "Fairies". Maybe it is because of famous contemporary works that blurred the line? Such as Ghibli's "Spirited Away" where the witch stealing peoples' name is also a fairy-like inhabitant of an "Otherworld" ; or "Jonathan Strange and Mr. Norrell" where the powerful wizard turned fairy-power The Raven King needs his true name to be summoned.
Yet the Earthsea world has everybody keep their true name secret, not just magic-wielders, ordinary folks too. Because, and we are getting into the interesting part... Because it is meant to be a cosmic and social thing for everybody, not just one specific type of people. And this is explained when you look at Earthsea's inspirations. While Earthsea became a staple of "traditional fantasy" in itself (becoming inspiration for "traditional" works like "Name of the Wind" or parody works like Discworld), it was created to be an un-traditional fantasy. Among its attempts at reinventing the genre, or subverting it, was the desire to create an un-European setting. It is still medieval European in essence (the dragons, wizards and a lot of the society is just very "standard fantasy"), but it is wrapped in a lot of non-European elements. And the whole Rule of Names/Law of Names/True Name system Le Guin created for her book was meant to be THE most un-European thing ever.
Because, before it appeared in fantasy, where did the "True Name Law" appear? Putting aside the monotheistic religions talks, of course. [This trope is found in Jewish beliefs, traditions and occultism, especially when the Kabbalah is involved - there is this famous emphasis on God's True Name and how it should be an unspoken secret. This logic was reused for the story of C. Clarke, "The Nine Billion Names of God", not to be confused with "Kill Six Billion Demons". In Christianity God's name is also powerful but hardly a secret - demons' name could however be secrets people neede to uncover, mainly during exorcisms, but it can be argued this is a rule of every exorcism ritual around the world, the name/nature/identity of the evil presence needs to be identified.]
Well, Le Guin's inspiration were the Chinese Dao/Tao concepts of "zhen ming", "true names", and "zhen xing", "true shapes", used to create talismans which have power over spirits and demons. And the social traditions of the First Nations of Northern America, where children received two names - one public name that changed with the events in their life, and a secret unchanging one they preserved so evil spirits could not steal it. And the Egyptian legends where Isis stole Ra's true name to gain power, or of the "ren" part of the being, the "name" surviving after death. And the Polynesian sacredness or taboo-nature of specific names. (I could mention the South-Eastern Asian habit of protecting children by changing their name when they got cursed, or giving them false temporary names to trick spirits, but I am not quite sure Le Guin used it, whereas I know she did take inspiration from China, Polynesia and pre-colonization America)
And this is the whole irony of the thing. The introduction of "True Names" in American fantasy was done in an effort to create a non-European ambiance and flavor. Yet today it ended up becoming the emblem of the most European thing ever - fairies. It is a fascinating "snake bites its own tail" - in half a century, from trying to get away from European folklore, the Americans returned it all to European folklore.