Hyrkoon

"The warrior maids of Hyrkoon, who wear iron rings in their nipples and rubies in their cheeks"

- Jorah Mormont

Hyrkoon is a region in the further east of Essos, on thee eastern side of the Bone Mountains. It is thus located far to the east of the Dothraki Sea, and northwest of Yi Ti.

City-states such as Bayasabhad and Samyrian are located in Hyrkoon.

Hyrkoon is famous for its fierce warrior-women, known for their decorative body modifications. The warrior-women of Hyrkoon go about bare-breasted with iron rings through their nipples, and rubies studded into their cheeks.

Geography
The city-states of Hyrkoon and their warrior-women have been mentioned since the first novel, when Daenerys Targaryen notes them in passing as she wanders through the Eastern Market of Vaes Dothrak. Otherwise, very little has been revealed about their culture and history. A major update came with the World of Ice and Fire sourcebook (2014) - but even then, it didn't really get a full section devoted to itself in the way that Yi Ti did, but just several large sidebars in the Dothraki and Yi Ti sections.

The formal name of Hyrkoon is actually the "Patrimony of Hyrkoon". The original Patrimony actually fell many centuries ago: due to being located in the rain shadow of the Bone Mountains, increasing desertification eventually destroyed it. The years-long seasonal cycles across both Westeros and Essos have gradually trapped a large amount of ocean water as polar ice over the millennia, lowering the sea levels and leading to desertification in many areas. Their empire was not totally destroyed, however, as three large fortress-cities built to guard the mountain passes along the western borders survived, and in time turned into independent city-states.

From north to south, these surviving Hyrkoon cities are Kayakayanaya, Samyriana, and [Bayasabhad. They are located high up in the inhospitable mountain passes, and apparently survive on heavy tolls that they exact on trade caravans from Yi Ti itself. The caravans from Yi to travel to Vaes Dothrak, Slaver's Bay, and Qarth. In Vaes Dothra, the Yi Tish caravans exchange goods with merchant caravans from the Free Cities (particularly Qohor), some of whom are selling secondhand wars all the way from Westeros (such as fine wines).

As used in The World of Ice and Fire, the demonym for people or things from Hyrkoon is itself "Hyrkoon" (compared to the demonym "Westerosi" for things from Westeros, or "Yi Tish" for things from Yi Ti). Its people are referred to collectively as "the Hyrkoon".

The publication history of the name "Samyriana" has undergone several errors, and attempts to fix it turned out to be typos themselves. The World map provided for the TV continuity in Season 2 gave it as "Samyrian" but this is itself an error.

Ran, the founder of Westeros.org and co-author of The Worlds of Ice and Fire book with George R.R. Martin, weighed in on the issue: while The Lands of Ice and Fire is meant to be the new canonical geography, the name "Samyriana" appearing on its maps is itself a misprint, and the proper spelling is indeed "Shamyriana". However, because the city was mentioned only once in the first novel, rather than live with a known misprint on the official maps, subsequent reprints of the first novel may just be revised to use the spelling "Samyriana". Either way, the name of the city is supposed to end in an "a", and the HBO Season 2 map is in error.

Culture
The maesters of Westeros are stated to only have sketchy reports about the history and culture of the Hyrkoon city-states (an in-universe explanation of why even the World book only gives a few scraps of information on them).

Only women can be warriors in Hyrkoon. One report the maesters have received indicates that this is due to some sort of religious belief held by the Hyrkoon, that only those who can give life (in childbirth) should be allowed to take it.

In some ways the fierce, terrifying warrior-women of Hyrkoon are similar to the Amazons of Greek myth - the older original versions of the myths that describe them as ruthless and bloodthirsty. On the other hand the Hyrkoon warrior maids don't live entirely without men.

The social structure of the Hyrkoon city-states is in some ways reminiscent of a eusocial species, like bees or mole-rats. Out of all the males born in Hyrkoon, 99 out of 100 are castrated and turned into eunuchs, who perform all non-martial tasks in society, from farmers to artisans, to healers, teachers, and priests. Essentially they serve as the worker drones of their society. Only the healthiest and most beautiful 1 in 100 are not castrated, and grow to manhood to become the true ruling class, the so-called "Great Fathers". Only the Great Fathers can sire children with the women of the cities, who are all warriors - and thus they are literally the fathers of most of the population. It is apparently for this reason that their empire was formally styled as the "Patrimony" of Hyrkoon.