If the question is
What's the most ancient known example of a woman challenging feminine gender roles?
then I understand that to mean mainly a real woman doing the 'challenging'. And of course within a society that first developed an increasingly patriarchical system in the first place. A more egalitarian hunter-gatherer community has not that much need or use for anyone "challenging feminine gender roles".
This would then not be someone like Plato just entertaining an idea, and quite general at that. But this Greek may have been somewhat inspired in looking from his own misogynistic society to Egypt, like his fellow Herodotus, who found the much more liberal customs in Egypt regarding women and their general status quite astounding.
That is, everyday women. Egypt has of course another list of contenders:
- Nitokret: 2148 - 2144 B.C.
- Sobeknefru: 1787 - 1783 B.C.
- Hatshepsut: 1473 - 1458 B.C.
- Nefertiti: 1336 B.C.
That is not queens, but kings with female reproductive organs, or 'womankings' (archive.org).
This is hitting quite the spot for our modern views, as the Egyptians didn't even have a name for such a construct and it seems so clear to us that Hatshepsut 'had to behave like a man', dress like a man and wear a beard like a man; one might even say in the official iconography she looks to us as what we would call also a cross-dressing or even transgender person:
Hatshepsut acted as the real ruler and she did so with the support of the temple community of Amun. To maintain their support, she built magnificent monuments in honor of the god Amun, notably one at Deir el Bahari (near Luxor), where the queen's reign was commemorated. In her statues and pictures she is usually portrayed as a man with a symbolic royal beard.
After her death Thutmose III tried to obliterate her memory, and later the Amun-hating Amenhotep IV (Ahknaton) tried to complete the task by removing all references to the god. These reactions, however, were apparently not due to the fact that she was a woman but for dynastic and religious reasons. The case of Hatshepsut emphasizes a theme that appears throughout this book: namely, that women cross dressed and impersonated men to gain what they could only achieve if they acted like men, while male cross dressers, as personified by the legends surrounding Sardanapalus, were portrayed as doing so for "erotic" or other reasons. Though men also cross dressed to disguise themselves in order to infiltrate enemy lines or achieve other short-term goals, repeated incidents of cross dressing seem to have stronger sexual connotations in men than in women. Some have argued that Hatshepsut's cross dressing involved more than adopting the necessary symbolism to rule and expressed her desire to change her sex, since some surviving representations of her portray her with a penis. Still, the fact that the pronouns accompanying the text are feminine make it clear she was a woman, and it seems to imply that the male clothing and appearance was a prerequisite to rule. The implicit lesson in the two stories is that for those who told them men lost status by cross dressing, at least if they did so in any serious way, while women who cross dressed overcame many of the barriers that handicapped them.
Vern L. Bullough & Bonnie Bullough: "Cross Dressing, Sex, and Gender", University of Pennsylvania Press: Philadelphia, 1993, p24.
If we do not restrict the search to confirmed historical, we might look at the bible, and find Deborah the judge, in a 'male' role, hard to explain away.
These examples from roughly the same region point again at the culture producing Inanna, or rather back at us and our expectations of patriarchal dominance in ancient times, first and last and always. We have an often distorted view on the actual need for "feminine disruptors of roles" in very ancient societies of historical time as well. The Sun goddess of Arinna had aspects that for a while just had to be male:
The name Ištanu is the Hittite form of the Hattian name Eštan and refers to the Sun goddess of Arinna. Earlier scholarship understood Ištanu as the name of the male Sun god of the Heavens, but more recent scholarship has held that the name is only used to refer to the Sun goddess of Arinna. Volkert Haas, however, still distinguishes between a male Ištanu representing the day-star and a female Wurunšemu who is the Sun goddess of Arinna and spends her nights in the underworld.
Again challenging our perception might be the archaeological source for the Amazons as real 'warrior women', doing quite a bit on the rough side, outside of the kitchen.
For more European, and even Greek "ideals" of how a women should behave, one might also look at
Cynnane knew well the politics of dynastic marriages; she was the product of one. Her mother, a princess of Illyria (today part of Albania), had come to Macedonia to wed Alexander’s father, Philip, and seal an alliance between two contentious nations. Cynnane grew up at the Macedonian court but stayed true to her maternal traditions, for Illyrian women were famously tough, capable of going to war as men did. In her teens Cynnane is said to have accompanied the Macedonian army on a campaign into Illyria and to have slain a queen of that country—perhaps one of her own relatives—in hand-to-hand combat. Unfortunately, no account survives of that encounter between two armed female leaders, the first such encounter known to European history—though it would soon be followed by another.
James Romm: "Ghost on the Throne. The Death of Alexander the Great and the War for Crown and Empire", Knopf Doubleday: New York, 2011.
Again, looking just at the timeline of religion: how should we categorise Tiamat or Sekhmet? Are both obeying our conception of female/feminine gender role? Or do we have a distorted lens in front of us, when analysing for example the Dancing Girl:
"She's about fifteen years old I should think, not more, but she stands there with bangles all the way up her arm and nothing else on. A girl perfectly, for the moment, perfectly confident of herself and the world. There's nothing like her, I think, in the world."