The Knowledge Treaty

The Great Cataclysm was a result of the Equestrian Leadership hiding information from the public, and even from those close to Princess Twilight Sparkle. She was worried about the statue that imprisoned Chrysalis, Tirek and Cozy Glow breaking, but wouldn't talk about it. When anybody would raise that issue she would lie and say it is impossible to break. Perhaps she just found it hard to rely on other people after the passing of her friends. Or perhaps she felt like she would fail Equestria if she couldn't solve the issue on her own. Or both. Regardless, she never solved the problem and the entierty of Equestria was destroyed. She failed everyone by lying and hiding the truth. 

By the end of her reign, no dangerous spells were available to anybody but herself. She collected any magical artifacts and completely erased their existence from history. Crime rate was as low as it could possibly be, and all were truly happy, so one could argue it was good. but in the end that prevented ponies and other creatures from finding a way to prevent the Great Cataclysm.

After the Great Cataclysm, a couple of leaders came together in order to find a way to prevent such events from ever happening again. They concluded that no creature should ever unite all species together and gatekeep their cultural heritage. That would make them vulnerable to loosing their cultures and the world's knowledge could be lost. They had to find a way to gather all of the World's knowledge and keep it safe. They concluded that the World's Cultural Heritage and Knowledge was more important than any life.

Those who signed the Knowledge Treaty were Queen Selenara of the Grifix, King Wolfwood of the Hippogriff, Queen Amethyst Flare of the Kirin and Changelings united, the Leader of Farasi and the Silent One.

The treaty implied that 4 enormous libraries would be built in the South, East, West and the North, the North one being the biggest and safest. 

The Great Southern Library is situated in the South of Equestria, on Mount Aris, but the most important artifacts are underwater, in Seaquestria. It is ran by Hippogriffs.

The Great Eastern Library is situated in the East of Equestria, in Farasi. It is ran by zebras, abada, kelpies and oni.

The Great Northern Library is deep in the Frozen North, in the grifix Frozen Empire. It is the biggest of them all, and the Treaty implies that all knowledge stored in the other libraries should eventually end up here. That is because grifix can't possibly create a united species empire, because nobody can see them, so there is no threat of history repeating. At the same time, the climate there is too harsh for anything to try to live there. Nothing could take over of that place, because once the grifix are gone it's impossible to live there. They are the only ones that can live there, so all information is safe from harm.

The Great Western Library is a mythical place. It was supposed to exist, but records of who the Silent One was have been forgotten by most, even tho they still exist in the Great Northern Library. If it was another species running this library in the west, they are believed to have went extinct by now, for nobody has heard of them in ages. 

Other than that, there's the Kirinaria Mercenary Group in central Equestria, right next to the Everfree Forest. Their "mercenary" title covers up their true purpose. They take jobs like any normal mercenary group and do people's dirty work, but they always keep an eye out for books and ancient artifacts, or anything that contains knowledge, like memory orbs. They temporarily store such artifacts in their camp until expeditions from one of the three libraries come to pick them up. Scholar Guild's grifix often send expeditions here.

There is however another reason for their placement next to the Everfree Forest. But first, it is important to know that the Great Cataclysm erupted from the Everdeep Lake, and caused a huge wave of radioactive water to hit Canterlot, so the area around Canterlot is the most damaged, mostly inhabitable, full of magic radiation. The Everfree Forest is almost entierly covered by a radioactive magic swamp. Still, what has become of the Tree of Harmony is still there, underground. And it hold some of the most important magical artifacts of all, more important than even the Elements of Harmony. That is what the Kirinaria Mercenary Group must keep watch of, in order to protect.

They don't live right next to it tho, because the radiation is too big there, they live a couple miles away, in an habitable area. Still, they are affected by slight radiation which causes their traits to act much more individually then in the past (for example, not all changelings look the same anymore).

Changelings and Kirin are united under one ruler because the changelings trust Amethyst Flare. When Chrysalis tried to take over them they refused because she showed signs of weakness in her actions, which they were disgusted of. Amethyst Flare may show compassion, but she never shows weakness so the changelings chose to follow her.

Most changelings in the Mercenary Group stay in their dark form, but it is unknown wether that's their true form or they just choose to shapeshift into that permanently. Kirin can now control their fire and use it to fight and kill if required.

Regularily, the Scholars Guild sends expeditions to the Kirinaria Mercenary Group or one of the two other libraries that are part of the Knowledge Treaty in order to bring artifacts and books to the Frozen Empire. Most grifix aren't aware of the Treaty, but it's usually cause it's none of their business, not because the information is kept away from them. 

The Crystal Empire Academy is not afiliated with the Knowledge Treaty, and the crystal ponies are not aware of it. The Crystal Empire has the 4th largest library in the world, tho they believe it is the biggest because they don't know of the Treaty. Members of the species part of the treaty do sometimes try to infiltrate and steal from the Crystal Academy so they can bring the Knowledge to one of the Knowledge Treaty libraries. However, in most cases they just transcribe books instead of stealing them.