Art by Luis Royo

Game of Thrones is an intense political and character drama brought to life by its fantastic settings and engaging actors, but it’s also chronicling events within a fantasy world that expands in rich detail through author George R. R. Martin’s A Song of Ice and Fire book series. Not all of these details make it into the TV show. (Frankly, not all of these details make it into the books themselves!) But knowing them can make Game of Thrones an even richer television experience.

Here are 15 secrets about Westeros and the characters that will make the show and the books even more incredible.

These details come primarily from The World of Ice and Fire, a massive, official, and beautifully detailed history compendium by George R. R. Martin that is available now.

1.) Mankind on Planet Westeros is young.

According to TWOIAF, the maesters of Westeros think that mankind only emerged 40,000 to 500,000 years ago, which is more than a million years younger than humans on Earth. The origins of humans on Earth can be traced to the grass plains of northern central Africa and it is suspected that the origin of humans in Westeros can be traced to a similar environment in the Dothraki Sea on Essos. The first signs of human settlements are along the rivers in the western portion of the Dothraki Sea, and cave paintings have been found west of that, south of the Free City of Norvos.

Other species on Planet Westeros are considered to be older than mankind: like the giants, the Children of the Forest, and quite possibly the Others.

2.) The fight against the Others isn’t just Westeros’ problem.

Thousands of years ago, Westeros went through a catastrophe known as “The Long Night,” where the White Walkers and Others swarmed down from the north and winter refused to relinquish its grip on the land. This catastrophe only appeared thousands of years after the First Men (essentially mankind) settled Westeros and diminished the population of the Children of the Forest. The freeze that crept down into the world also affected Westeros’ neighboring continent of Essos, freezing the Rhoyne river down to the same latitude as Dorne, nearly to the southern coast of Essos.

3.) A supervolcano altered the course of the known world.

Before Westeros was fully settled and magic faded from the world, there was an advanced magical empire known as Valyria, located on a peninsula to the southeast of the Free Cities of Essos, which was the reigning power in the known world. Dragons were plentiful here and the Targaryen family can trace their lineage to this empire. (You may have noticed that swords made of Valyrian steel are highly prized items in the TV show.)

Valyria vanished in one fell swoop known as the Doom, leading to the political and national structures we know in Game of Thrones. Although there were many antagonistic forces wishing for the Doom of Valyria, the physical evidence of the now-shattered peninsula overwhelmingly suggests that Valyria sat on top of a supervolcano/caldera.

Many rare minerals and substances were located on the Valyrian peninsula, so ironically the Valyrians may have saved the world from that same caldera by overmining it over the course of centuries and subsequently releasing some of the pressure building up before the eruption. While the Doom still came, the blast and subsequent ash cover could have been significantly more powerful and catastrophic to the planet at large.

4.) Samwell Tarly is not to be trifled with!

Our beloved Samwell Tarly of the Night’s Watch is not the first of his name. A “Savage Sam Tarly” wielded a Valyrian sword by the name of Heartsbane during the reign of Aenys Targaryen I, hundreds of years ago, and slew many a Dornishman while hunting for a rebel called the Vulture King. It was said that his sword was stained red from the blood of countless Dornishmen.

5.) Hardly anyone is the first of their name.

Names repeat quite often in the histories of Westeros and the kingdoms beyond, and there has been more than one Daenerys, Viserys, Lancel, Jeyne Westerling, Sam Tarly, and so on. There’s even another Joffrey with questionable parentage!

6.) Piousness almost brought down Westeros’ communication network.

The Targaryen line ruled Westeros for hundreds of years before the events of Game of Thrones, and like any ruling system based on a hereditary line, having the Targaryen name didn’t automatically denote a shrewd, good-hearted badass. For example, an ancestor of Dany’s called Baelor Targaryen (known as the “Blessed”) instituted a lot of impractical reforms based on his overzealous faith of the Seven, but the funniest ones were probably his insistence that doves replace ravens as a means of communication, and that an illiterate boy named Pate be made the High Septon. Both events were debacles, and quickly reversed.

7.) The Muppets are House Tully.

George R. R. Martin likes sneaking lots of real world references into the margins of his world. (Tor Books even shows up as a house in Dorne!) During a civil war known as the Dance of the Dragons, Ser Elmo Tully declared Riverrun for Rhaenyra Targaryen instead of Aegon Targaryen II. He lived only 49 days before dying and leaving Riverrun to his son…Lord Kermit.

8.) What’s west of Westeros?

No one knows. The Iron Islanders have made repeated voyages over the massive ocean known as the Sunset Sea to find out, but have turned back reporting no sightings of land.

There are two structures on Westeros that hint at a civilization visiting Westeros from over the Sunset Sea. One is the Seastone Chair, found already standing in the Iron Islands before it was settled. The other is the base of the Hightower in Oldtown, a black stone square with hallways that feel more like walking through a smooth tunnel a worm has made through the rock. So far, neither of these structures has appeared in Game of Thrones.

9.) Westeros gets hurricanes.

According to The World of Ice and Fire, hurricanes form in the Summer Sea and curve up into the Narrow Sea, making landfall every autumn* on the Westeros Stormlands on the eastern portion of the continent, in the same manner that they do in the Carolinas and Florida in the U.S.

*They are more frequent in the autumn between long summers and winters, but form in other seasons, as well.

10.) Braavos is way ahead of everyone.

Possibly thanks to a long history untouched by war or extended battle, the Free City of Braavos—which we’ll see more of in season 5—possesses technology and social constructs akin to advances made during Earth’s western Renaissance and Industrial Revolution. There is a building called The Arsenal which features interchangeable manufacturing ala the Industrial Revolution and which can produce an entire ship in a single day. The city also possesses aqueduct technology, hospitals, and the world’s largest bank.

11.) Westeros was severed from Essos by…global warming?

There was once a bridge of land that connected the eastern tip of Dorne to the continent of Essos, making Westeros and Essos one unbroken land. This strip of land was broken in the past and one of the theories as to why involves the Children of the Forest drowning the land bridge with their magic in order to halt the progress of the First Men.

Alternately, another theory blames the climate change that would result on a planet with uneven winters and summers, touting that a long series of extended summers and short, warm winters melted polar ice and made sea levels rise, turning the land bridge into the islands known as the Stepstones and merging what may have been a freshwater sea north of Dorne with the Narrow Sea.

12.) MORE DRAGONS.

The largely unexplored continent of Sothyros (found south of Essos) still contains wyverns, which are savage and smaller offshoots of dragons, and it is rumored that proper dragons still exist in the darkness beyond Asshai, which lay east beyond the Dothraki Sea and Qarth.

There are also hundreds of eyewitness reports of ICE DRAGONS (!!) roosting in the frozen regions of the Shivering Sea, the vast ocean north of the continent of Essos. Ice dragons are mainly known for their presence in bedtime stories to the children of Westeros, but perhaps Daenerys’ children may encounter White Walkers on ice dragons at some point?

(Or this guy?)

13.) Snails are big money.

The key to the Free City of Tyrosh’s wealth? Snails. That excrete rich dyes and are only found in Tyrosh.

14.) The joining of Stark and Targaryen is key.

In Westeros’ history, Lord Cregan Stark made an agreement with the Targaryens during Aegon IIIs reign called the “Pact of Ice and Fire,” designed to wed Stark and Targaryen to each other.

It went unfulfilled. For now.

15.) Many people will be required to turn back the White Walkers and the Others.

Want to know how the characters in Game of Thrones will stop winter from coming? Look to the fabled heroes that halted The Long Night the first time it came. Each culture in Westeros, Essos, and beyond names a different kind of hero, and the nature of many of these heroes seem to be earlier versions of the characters we follow in the series.

The Asshai credit Azor Ahai and Lightbringer for ending the Long Night. Stannis or Jon Snow?

Stannis or Jon Snow? Credit is also give to a mystery hero who traveled through the North with his companions abandoning him or dying before he reached the Children of the Forest and pleaded for their intervention. Which we’ve essentially just seen Bran do.

An Essosi legend credits another mystery hero who got lesser gods (such as the “Crab King” and the “Old Man of the River”) to stop fighting each other and “sing a secret song” to combat the Long Night.

The Yi Ti claim that disaster was only averted through “the deeds of a woman with a monkey’s tail.” Daenerys, under the advisement of Tyrion?

The most boring theory is, of course, that the Night’s Watch did all the hard work of physically fighting them back, which seems more likely than any magical intervention. After all, it wasn’t magic that held back the Wildlings these past few seasons, but dedicated Night’s Watchmen.

Will any of these secrets become vital as Game of Thrones marches towards its conclusion? Probably not, but they’re nevertheless a part of the history and firmament that resulted in the characters and environment that keep us fascinated with A Song of Ice and Fire and its acclaimed TV show. That context helps us better visualize the chaotic world that these characters move within, and makes it all the more satisfying when their actions inevitably change that world.

Winter is coming. But now we know…it has come many times before.

This article originally appeared on Tor.com in an altered form in October 2014.

Chris Lough left out the part about the dragon eggs.