The world of Game of Thrones is so consumed with war, plight, and existential threats that the humble work of the teachers, record keepers, healers and researchers often goes unacknowledged. Maesters have been present throughout the show and books, offering their services and counsel to the lords of locations all over the realm, from Winterfell to King’s Landing.

We haven’t really gotten a look at the lives of these learned servants. However, now in season 7, with the curious and altruistic Samwell Tarly, we are getting an inside look at the lives of maesters and maesters in training. Sam’s training comes with a bit more urgency than most maesters. He’s escaped from White Walkers and is on a mission from his friend Jon Snow to learn all he can to help prepare the realm for the coming Winter.

What else can Sam expect at the Citadel? How does the Order of Maesters operate and pursue knowledge? How have they applied themselves to their duties while we’ve been distracted by battles, dragons, and sexposition? There is a lot to learn about this learned order of Westeros.

Here are the 15 Things You Didn’t Know About The Maesters.

15. THEY WERE PRECEDED BY THE ALCHEMISTS GUILD

Before the Order of Maesters was the foremost intelligentsia in Westeros, there was the Alchemist Guild. As their name would imply, they claimed to be able to transmute metals and create great creatures of living flame.

The height of their power was during the reign of King Aerys II Targaryen, the Mad King. Various Targaryen kings had employed the services of the Alchemist Guild before, but the Mad King took much greater advantage of it.

The Mad King used wildfire made by the Alchemists Guild to punish perceived traitors and rebels in his kingdom. Ned Stark’s father and brother met this fate. When Robert was looking to be victorious in his rebellion, the Mad King ordered the Alchemists to lace King’s Landing with wildfire and be prepared to incinerate the city at his command.

After the Targaryens fell, the Alchemists Guild diminished in hip and prestige. Despite falling out of royal favor, Tyrion did consult with Alchemist Guild master Wisdom Hallyne to lay a wildfire trap for Stannis Baratheon’s fleet.

14. THEY ARE SOMETIMES CALLED THE KNIGHTS OF THE MIND

The maesters are definitely less archaic compared to the Alchemists Guild. Their pursuits are mostly in more verifiable, academic subjects like mathematics, medicine, ravenry, and letters.

Since Westeros is still a medieval society, knights are one of the most esteemed roles in society as masters of warfare. Thus, as maesters are the foremost learned men in Westeros, their order is sometimes referred to as the Knights of the Mind.

We haven’t actually heard this phrase used in the show yet, but early on in the books, Bran asks Maester Luwin at Winterfell about magic. In that conversation he says:

“There are some who call my order the knights of the mind ... Have you ever thought that you might wear a maester's chain? There is no limit to what you might learn ... I can teach you history, healing, herblore. I can teach you the speech of ravens, and how to build a castle, and the way a sailor steers his ship by the stars. I can teach you to measure the days and mark the seasons, and at the Citadel in Oldtown they can teach you a thousand things more. But, Bran, no man can teach you magic.”

13. THE CITADEL WAS FOUNDED BY HOUSE HIGHTOWER

Before the Targaryens established King’s Landing as the Capital of the Seven Kingdoms, Oldtown was the largest city in Westeros by far. It has grown over the centuries from consistently bustling trade, resting at the mouth of the Honeywine River in the fertile land of the Reach. House Hightower have been the lords of Oldtown since the Age of Heroes thousands of years ago. Their keep-- the Hightower-- is another colossal structure that Oldtown boasts.

Sometime long before Aegon’s Conquest, Peremore Hightower, second son of King Uthor of the High Tower, was born. He was born sickly and misshapen, but he had an insatiable curiosity about the world.

He invited numerous scholars, wise men, teachers, priests, healers, singers, wizards, alchemists, and sorcerers to Oldtown to share and expand their knowledge. When Peremore died young, his brother, King Urrigon, bequeathed a plot of land to the learned group who then established the Order of Maesters and built the Citadel.

12. THE CITADEL HOUSES A MASSIVE RAVENRY

The Citadel is comprised of several grand structures. At the main gates sit a pair of giant green sphinxes. Inside are the Scribe’s Hearth, where acolytes offer reading and writing services, and other areas of study and housing. Not to mention the massive library with elaborate mirrors to illuminate the maesters’ bookish pursuits.

There is one part of the Citadel premises that is older than the Citadel itself. In Oldtown’s ancient history, there was a massive Ravenry on an isle in the mouth of the Honeywine.

According to some legends, it was once ruled by a pirate who used it as a stronghold to attack ships ing down the river. When the Order of Maesters was established, the Isle of Ravens was incorporated into the Citadel.

It houses hundreds of ravens, both black and white, that perch upon the walls, vines, and the branches of a weirwood in the center courtyard. As the most effective means of widespread communication in the realm, raven tending is one of the most crucial duties and common studies among all maesters.

11. THEY ARE RULED BY A GOVERNING BODY CALLED THE CONCLAVE

The Order of Maesters is organized by a hierarchy. Novices must study enough to become acolytes, who must then study enough to become full maesters. At the citadel, there are designated fields of study.

When a certain maester becomes the most learned in a field, they become the archmaester for that field. As the most senior of the Order, archmaesters are permitted a seat on the Conclave. The Conclave-- made up of the archmaesters-- governs all aspects of the Order’s practices.

The Conclave also elects the Grand Maester, who is chosen specifically to advise the King and represent the Citadel and the Order at court. Only the Conclave and appoint or remove a Grand Maester.

Each year, a Seneschal is chosen by lottery from among the archmaesters, and is tasked with governing the Citadel itself. Most archmaesters disdain the post, as they feel that it distracts from their true calling of research.

10. THE MAESTERS HAVE MANY SIMILARITIES TO THE NIGHT’S WATCH

The Maesters and the Night’s Watch are two organizations on nearly opposite sides of the continent of Westeros, but they have a surprising amount of similarities.

They are both supposed to be neutral when it comes to the noble and royal politics of the realm. Lord Commander Mormont said that the Watch’s commitment is to guarding the Wall, no matter who sits the Iron Throne, and we’ve seen maesters serve different lords of the same castle, even enemies. Both orders require celibacy in their oaths and call for their to forsake any former family names or titles.

In practicality, there are still important differences. You could argue that maesters enjoy a bit higher stature in society than men of the Night’s Watch. While most novices arrive by choice at the Citadel, most of the Night’s Watch recruits are criminals or unwanted sons.

Although, as we’ve seen with Maester Aemon, there are a handful of people who belong to both orders. Hopefully Samwell Tarly will earn that distinction.

9. IN THE BOOKS, THERE IS A KEY THAT CAN OPEN EVERY DOOR IN THE CITADEL

The show has really given us a visual sense of how vast and intricate the halls of learning are at the Citadel, not unlike a university campus. We haven’t seen much in the way of security or guards in the Citadel.

Presumably, Oldtown has been left mostly untouched by the raging wars throughout the show. In the books, there is at least one exploitable security flaw. The archmaesters each carry a key that can unlock any door in the citadel. Only archmaesters may carry such keys.

We haven’t seen a key like this in the show yet, but in the books, archmaester Walgrave’s key is stolen by an acolyte named Pate. Pate gives the key to a mysterious man, a faceless man, who may very well have been Jaqen H’ghar.

After Pate gives him the key, the faceless man poisons the poor acolyte. What secrets from the Citadel would a faceless man need to steal and kill for? Perhaps these scenes may make it into the show in some way.

All of the maesters we’ve seen in the show wear chains over their robes which are made up of links of various shapes and sizes. The chains seem quite burdensome, but they are actually very symbolic.

Each of the metals that the links are made of signify a field of expertise that the maester has mastered. A chain or link made of iron represents knowledge of warcraft, while silver is for anatomy, medicine, and biology. There are more than a dozen different fields with a corresponding metal, although not all of them have been specified in the books.

Maesters forge the links of their chains personally as they progress in their studies, adding to their collar that shows their hip in the order. Their collars overall represent their duty as bound servants of the realm and or whichever keep they are assigned to.

Maesters are supposed to wear their chains all the time, even while sleeping. In addition to chains, archmaesters are granted masks, rings, and rods that are made from the metal corresponding to their field, to signify their preeminence.

7. SOME CHARACTERS HAVE STUDIED AT THE CITADEL WITHOUT BECOMING FULL MAESTERS

Based on what we’ve seen in the show, The Citadel doesn’t seem like a university, where any one can come and study and then continue with their lives outside. If you want your studies to be recognized, you have to progress from novice to acolyte to maester, and then fulfill your assigned duties at whichever keep you are given.

We’ve met characters in the show who haven’t gone down that path, though. Oberyn Martell, the Red Viper of Dorne, was well versed in poisons through his studies at the Citadel. It was one of the many things he was notorious for, along with his fighting skills and grudge against the Lannisters. He forged several links in a maester’s chain before reportedly growing bored and quitting.

Oberyn’s path is likely not typical even among Westeros nobility. His status probably permitted him to study at the Citadel on a temporary basis, unlike Samwell Tarly, for example. As Varys told Oberyn, “most of us aren’t princes.”

6. ALL ACOLYTES SPEND A NIGHT WITH A GLASS CANDLE

All maesters at the Citadel begin as novices no matter their age. Eventually they are tested and can forge a single chain link in a single discipline to advance to the rank of acolyte. When an acolyte has forged enough chains, they are deemed worthy of becoming a full maester.

On the night before they take their vows, all would-be maesters are required to spend the night in an empty room with nothing but candles made of dragonglass. These ancient obsidian candles were once used throughout Old Valyria. They gave off otherworldly light when lit and were said to allow sorcerers to peer across the world.

In the books, by the time of the main series, no one has seen a lit obsidian candle or knows how to light one. The overnight vigil with the obsidian candles is meant to impress a final lesson of humility with the maesters. Even with all their knowledge, there are still mysteries in the world that cannot be solved.