I don't wanna be a guy asking to be spoonfed, but do you have any sort of quick binder of articles/info for this? I hear troons talk about how they've existed since the dawn of man (trying to lump themselves in with the historical fags much like how they're stuck on inside of "LGBT") and they don't provide facts, but I sure would like to.
I am not aware of any articles, most historians are not interested in the topic, and would not touch it anyways because they know what the result of it would be.
The "pro" literature, if you can call it that, has either be done by gender studies, which is a meme faculty that never consults with the historical one because they don't like what they get back, and of course, journos.
I can give you a few bullet points.
There is one historical Roman Emperor they claim, because he was a cross-dressing homosexual who wanted straight men to fuck him. Not a joke. And that is the historical figure with the most support of being "trans". They tried to claim other complete bizarre ones like Paracelsus, because he didn't have a beard. Again, not joking. They argue that he was a transman.
In the societal sense, they try two different avenues.
The first one is effeminate homosexuals that have a sort of "special" position in society. The Indian "third sex" or the Philippine ladyboys would be examples.
You could atleast argue that those can fall under the modern trans umbrella, the problem is that it is not universal. Only a few handful of cultures have examples like this, and gender-flipped it pretty much never happened. It is always a subculture of crossdressing/homosexual men.
The other one is just blatantly wrong, and pissed me off to no end.
Different cultures, especially primitive ones, have sometimes special exceptions for a sex to change their legal status, or change it from the norm to an accepted exception.
One example is that women on the Balkans could take the status of a "man" to take over a mountain-ranch, together with an enforced requirement that she remains celibate and has no children.
Some germanic tribes had some remnants of matriarchy lingering. Normally, the husband would take the wife into his family, and he is the head of the household. There was a possible exception for noblewomen who wanted to inherit, they could marry a "lesser man", so one of lower societal standing, and she would be the head of the household.
Similar concepts exist in several tribes.
Now, it is obvious that this has nothing to do with changing sex, even "gender" in any way comparable to modern troonism. Those are legal and societal exceptions, not fucking introperspective lifestyle choices.
I could write up some articles about that, but I am lazy, and it wouldn't do much without giving my clearname and academic credentials, and I am not going to ruin my life for it.