- "It's a big and beautiful world. Most of us live and die in the same corner where we were born, and never get to see any of it. I don't want to be most of us."
- ―Prince Oberyn Martell
The world of Game of Thrones has no overall or official name. Characters within the story simply refer to it as "the world". At the time of the series, the known world consists of three discovered continents: Westeros, Essos, and Sothoryos. There are also numerous islands and archipelagos, including the Stepstones, Summer Islands, and Ib.
- Westeros: Located in the far west of the known world, Westeros extends southwards from the northern polar icecap for approximately 3,000 miles. Most of the continent is unified as a political entity called the Seven Kingdoms, ruled from the King on the Iron Throne in the city of King's Landing. Most of the action in Game of Thrones occurs in Westeros.
- Essos: Separated from Westeros by the Narrow Sea, Essos extends eastwards for many thousands of miles. It is larger than Westeros but less densely populated. The western edge of the continent is controlled by the nine Free Cities, while the city-states of the Bay of Dragons are located in the south-central region. Further east is Qarth and the fabled Jade Sea, which Essos partially encloses. The far eastern coast of Essos is unexplored, as it lies beyond legendary Asshai and the forbidding Shadow Lands. Much of the continental interior west of the Jade Sea is ruled by the tribal warriors known as the Dothraki.
- Sothoryos: Relatively little known, Sothoryos is located south of Essos, on the far side of the Summer Sea. It is a large continent consisting of deserts and jungles. It is said to be a haven for plagues and dangerous animals, and has not been explored much beyond the northern coastal regions.
Seas and oceans
- The Sunset Sea lies to the west of Westeros. No-one has successfully crossed the Sunset Sea with any reliable information about any landmasses that might lie beyond.
- The Summer Sea lies to the south of Westeros and Essos, dividing the latter from Sothoryos. It contains the Summer Islands. The extent of the ocean south of the Summer Islands is unknown. Inlets of the Summer Sea include the Bay of Dragons and the Gulf of Grief.
- The Shivering Sea lies to the north-east of Westeros and the north of Essos, separating the latter from the northern polar ice cap. Ibben and Skagos are the most notable islands of size in the Shivering Sea. During the winter, the Shivering Sea becomes much more hostile to cross.
- The Narrow Sea divides Westeros from Essos, and also connects the Summer Sea in the south to the Shivering Sea in the north. While smaller than most of the other seas, it is still several hundred miles wide, presenting a formidable obstacle to military activity between the two continents. During winter, the Narrow Sea becomes difficult to cross because of storms and strong winds blowing from the north. Inlets of the Narrow Sea include Blackwater Bay, the Sea of Dorne, and the Sea of Myrth.
- The Jade Sea lies in the far east of the known world, beyond the plains of the Dothraki and Qarth. The Straits of Qarth (also called the Jade Gates) connect the Jade Sea with the Summer Sea, making Qarth a major hub for west-east sea trade. Yi Ti and Asshai are located along the coasts of the Jade Sea. Bold traders get rich from performing the "trader's circle" around the Jade Sea, trading between the powerful city-states and merchant kingdoms of the distant east and then carrying those riches back to Westeros and the Free Cities. Such a journey may take two years or more.
This is not a definitive list, but major islands or island groups of particular size and significance:
- The Arbor is a very large island off the south coast of Westeros. It is part of the Reach, held by House Redwyne and owing fealty to House Tyrell. It is one of the main wine-producing regions of the Seven Kingdoms.
- Bear Island lies off the north-western coast of Westeros. It is controlled by House Mormont and owes fealty to House Stark.
- The Iron Islands lie off the west coast of Westeros. They are one of the major regions of the continent and are controlled by one of the Great Houses of the Seven Kingdoms, House Greyjoy of Pyke.
- The Three Sisters are a collection of three small islands located between the North and the Vale, in a large bay called the Bite. For centuries they have been a haven for pirates and smugglers, but they are not nearly as large as the Iron Islands, so their raiding is looked down upon as mere piracy, and more of a nuisance than a threat. Officially they are ruled by the Vale, though their allegiance is always tenuous.
- Skagos is a large island off the northeastern coast of Westeros. In theory it owes fealty to House Stark, but in practice its savage inhabitants (who are rumored to be cannibals) are allowed to go their own way. Skagos is the largest of several islands in the archipelago, which also includes Skane.
- Tarth, Dragonstone, and Estermont are large islands in the Narrow Sea, off the eastern coasts of the Seven Kingdoms.
- The Stepstones are a group of islands dividing the Narrow Sea from the Summer Sea. Legends say that in ancient times they formed a land bridge between Westeros and Essos. The present-day island chain is still one of the major paths of transit between Westeros and Essos, as merchant vessels follow their shallow waters instead of the open ocean, and any north-south sea traffic must also pass through them. The Stepstones are one of the world's major pirate dens, preying on all of the sea trade going around them. Efforts are often made to clear the Stepstones of pirates but new ones always replace them. The Free City of Tyrosh is located on the easternmost of the Stepstones. Several of the Free Cities, including Tyrosh, Lys and Myr, constantly compete for control of the islands, as does the Iron Throne of the Seven Kingdoms on occasion, but any gains are temporary. Overall they remain a lawless no-man's land ruled by pirate-lords.
- The Free City of Lorath lies on an off-shore island in the Shivering Sea, while Lys is located on an off-shore island in the Summer Sea.
- Ibben, sometimes called Ib, is the second largest island in the known world, home to a civilization of seafarers and whale-hunters. It is located thousands of miles east of Westeros, off the north coast of Essos (hundreds of miles north from Vaes Dothrak). The Ibbenese trade across much of Essos and sometimes in Westeros as well. It is far too small to be considered a continent in its own right (about the size of real-life Iceland), and is loosely considered to be part of Essos.
- A great archipelago lying south-east of Volantis and west of the Bay of Dragons is the shattered remnant of the great Valyrian empire, obliterated four centuries ago in a cataclysmic volcanic event known as the Doom. Sailors from across the world know to give Valyria a wide berth, as volcanic activity continues there and the Smoking Sea between the islands is said to be uncrossable, as the fumes rising from the water can choke a man to death.
- New Ghis, lying on an island on southeast to the Bay of Dragons, is the capital city of the resurgent Ghiscari Empire, which once sprawled across the nearby mainland until it was destroyed by the Valyrian Freehold five thousand years ago. Since Valyria's fall, the Ghiscari have sought to rebuild their empire with slow results.
- The Basilisk Isles lie off the north coast of Sothoryos and are said to be home to many dangerous and fabled creatures. The Basilisk Isles and nearby Naath are frequently raided by slaving ships from the north.
- Naath is a major island off the north coast of Sothoryos, west of the Basilisk Isles chain. Its pacifistic inhabitants are a favored target for slavers.
- The Summer Islands lie southeast of Westeros, far west of mainland Sothoryos, even further west than Naath. They are a large cluster of islands ruled by their own independent princes. The Summer Islanders are one of the great maritime powers of the world, whose famed merchant ships are found in ports across Westeros and Essos.
Climate and seasons
A major feature of the world the narrative is set in is that it experiences long seasons of varying length, usually lasting at least a couple of years each. Historically, the seasons have been known to last up to a decade in extreme cases, though these only happen once every century or so. The length of the seasons is completely unpredictable and varies randomly. There is some very loose correlation that a long summer is often followed by a long winter, but this is more of a trend than a rule. Conversely, seasons may be unpredictably short: the Year of the False Spring was so-named because an entire spring season occurred during it which lasted only two months. The maesters of the Citadel keep a close eye on the length of the days in order to try to predict how long the current season will last, but this is an inexact science at best. The continent of Westeros extends much farther north than the continents of Essos and Sothoryos, and so is much more adversely affected by long winters. Meanwhile, Essos and Sothoryos are closer to the equatorial regions, which are typically warmer.
Even so, there are hints that the seasons may not always have been this way: characters still define "a year" as a twelve month period, not a full cycle of summer to winter. Months are the same as in real-life, roughly a thirty day period; the term "moon-turn" is commonly used for "month".
There is a suggestion that the long seasons are not naturally occuring, but may have a magical origin, stemming from a near-mythical event called the Long Night eight thousand years ago, when it is said that the White Walkers used the cover of a winter that lasted a generation and a night that lasted for years to invade Westeros. They were defeated in the War for the Dawn, thrown back into the furthest north and prevented from returning by the raising of the Wall, but the seasons never recovered. Maesters are highly skeptical of this story, dismissing it as folklore, despite the inarguable presence of the Wall.
The unpredictable and years-long seasons of the world Westeros is in are in some ways more akin to mini-Ice Ages and warming periods, such as happened in the real-life Earth, though never to this degree. The "Medieval Warm Period" was a period of rising average temperatures across the northern hemisphere from the years 950 to 1250, which was followed by the "Little Ice Age", an equally long period of falling average temperatures. The major difference is that these "mini-Ice Ages" occurred gradually over a period of two or three centuries on real-life Earth: Westeros, in contrast, can shift within a matter of years or months into a bitterly cold "winter" lasting a decade. There is still some variation in temperature across a normal "calendar year" in Westeros, so that what should be winter months in a normal 12 month year do tend to be slightly colder than the rest. Because the North is located at a higher latitude it experiences such variation to a greater degree, and is known to experience "summer snows" during years-long summer seasons (i.e. during what should be winter months in a normal 12 month seasonal cycle). Such "summer snows" in the North are mentioned by Pycelle in Season 1's "Cripples, Bastards and Broken Things".
At the time the TV series opens, the world has been experiencing a summer that has lasted for nine years, which is unusually long, and the maesters fear that a similarly long (or even longer) winter will follow. According to Tyrion Lannister, Westeros has experienced nine winters during his lifetime, the last ending about nine years before the beginning of the TV series. Tyrion states that the winter during which he was born was the longest of these, lasting three years. Thus, for the past thirty years or so, each full summer-winter cycle has lasted on average about 5–6 years. Autumn arrives the following year (in Season 2), bringing the ten-year long summer to a close.
The peoples of the world can survive years-long winters because they adapted to this climate pattern centuries ago. Lords set aside vast amounts of non-perishable food items for storage against the next winter. Some castles, like Winterfell of House Stark, have elaborate greenhouses which permit the growing of vegetables even in the harshest winters. In the North of Westeros, which is badly affected by cold winter weather, many notable strongholds are built in favorable areas, such as Winterfell which is built over hot springs, or the Dreadfort of House Bolton which is built on volcanic vents. Despite these precautions, famine and starvation is common during Northern winters, and is one of the reasons the North has a small population despite its vast size.
Shape and Size
As stated in the World of Ice and Fire sourcebook (2014), the Order of Maesters in Westeros, and other learned men across the world, have studied astronomy for centuries, and by observing the movements of stars across the night sky, have determined with relative certainty that their world is a round globe. Isolated tribes or simple farm peasants in Westeros who have no education, of course, might still colloquially believe that the world is flat, but they are mistaken.
The maesters also understand that theoretically, a ship should be able to circumnavigate the globe, by continuing to sail west from Westeros until they come around to Yi Ti on the other side, then continue going west until they return to Westeros. They also understand that a ship could sail north over the pole and reach Yi Ti on the other side - provided that there is no landmass or arctic ice in the way. However, as of yet no ship has ever successfully circumnavigated the globe. Ships that have sailed west of Westeros and returned report finding only a vast ocean, and other ships simply never returned. Even the far south of Sothoryos and eastern end of Essos are unknown to men in Westeros. There have been some attempts to navigate north over the pole, but all have ended in failure due to dangerous ice and other unknown dangers.
Martin himself stated back in 2002:
- "Yes, the world is round. Might be a little larger than ours, though. I was thinking more like [Jack] Vance's Big Planet....but don't hold me to that."
Westeros and the other lands in the known world are apparently located in their planet's northern hemisphere: the climate gets colder to the north extending into polar regions, and warmer progressing south towards the equator (it would be the opposite if in the southern hemisphere). Martin has said that Essos isn't quite as badly affected by the years-long winter seasons because it is closer to the equator, but he has never identified exactly where the equator is - or even if it is known. That is, it is unconfirmed if the equatorial line runs through Sothoryos and the Summer Isles, or, if the equatorial line is even farther away to the south, and is unknown even to explorers from the Summer Islands. Sothoryos has not been fully explored, but a handful of travelers' reports indicate that it is at least as long north to south as Essos is long west to east.
Nonetheless, while their globe is bigger than real-life Earth, it is not so utterly vast that that everything from the Wall to the Summer Islands is in the same climate zone: there is noticeable variation from polar regions to tropical regions. For all we know, however, regions like the Summer Islands which we would consider to have "tropical" climates are actually located in their world's "sub-tropics", and the "tropics" around their equator are so hot that they are truly uninhabitable to humans. Another hint about their world's size is that constellations in the night sky are noticeably different between the Wall and southern latitudes such as Dorne and the Summer Islands, meaning that the curvature of the globe is noticeable across such a distance (if their world were 100 times the size of Earth, the angle of curvature would be so low that they wouldn't be able to see different constellations between these latitudes).
Little is known of the "solar system" and astronomy of the world Westeros is set in, though in general, it appears to be roughly identical to real-life Earth. Astronomy is rarely mentioned and not very important to the narrative, but there has never been any indication that it is particularly different from real-life. The world in the fictional narrative has one sun. One moon orbits the world, going through lunar phases that make up a "month" (known as a "moon-turn"), equal to a real-world month.
The solar system that the world is set in is known to have seven other planets besides the world the story takes place on. The peoples of the world don't appear to realize that these are other worlds like their own, i.e. that people can stand on (it's not even clear if they understand that the Moon is another "world" people can stand on). Planets are termed "wanderers" as they move across the night sky relative to the stars, which are fixed (incidentally, in real life the word "planet" comes from the Ancient Greek word for "wanderer"). On real-life Earth, ancient cultures (such as Classical Greece) only knew of five planets in the night sky, not seven. However, this does not necessarily mean that their solar system is different from our own, just that their rate of discovery is different. Uranus was only discovered in the seventeenth century, and Neptune in the nineteenth, using astronomical telescopes: even Galileo in the sixteenth century, using his simple telescope, was able to detect Neptune, though he mistook it for a star and thus is not credited with its discovery. However, the people of the world that Westeros is set in actually do possess simple telescopes, which are frequently used to aid astronomical observations of the night skies. The best telescopes, which they call "far-eyes", come from the master-lenscrafters of the Free City of Myr, and are thus referred to as "Myrish-eyes". Therefore, it is entirely possible that they discovered their equivalent of Uranus and Neptune already, because they possess a few technologies such as basic telescopes which real-life medieval Europe did not yet possess.
It is unclear if the seven "wanderers" (planets) have formal names in the narrative . The only individual one identified was simply called the "red wanderer" - apparently their analogue of Mars. In the Seven Kingdoms it is associated with the Smith from the Faith of the Seven, though the Free Folk call it "the Thief" - because when the red wanderer appears in the constellation of the Moonmaid, they consider it a good time of year for a man to ritually "steal" a woman from another village to take as a bride.
While there is no apparent physical difference between the astronomical bodies of the fantasy world and real-life, certain culture-specific aspects are different, specifically that cultures in Westeros developed different constellations than those in real-life. There is no indication that the stars are outright arranged differently. Rather, because the Ancient Greeks did not exist in their world, logically, figures from Greek mythology such as "Orion" were not used as shapes for constellations: they played "connect-the-dots" differently with the stars in the sky, using figures from their own mythology. For example, one constellation is known as the "Crone's Lantern", referencing the Crone from the Faith of the Seven. Another constellation referred to several times in the novels is the Ice Dragon.
Their solar system also has minor astronomical bodies, such as comets and meteors. The Red Comet appeared in the sky near the beginning of the War of the Five Kings. Now and then small meteorites have been known to crash into the planet as well: Dawn, the ancestral sword of House Dayne, was forged from the metal recovered from a "fallen star" (House Dayne even uses a falling star in their heraldry as a result). Dawn has unusual properties: it is as strong and sharp as Valyrian steel (which is forged using spells and dragon-fire), but the metal of the blade is the color of pale white milk.
Setting and Conception
Author George R.R. Martin has stated that his fictional universe is meant to be a completely alternate and separate world not linked to our own in any way, specifically in contrast with J.R.R. Tolkien's Middle-earth legendarium or Anne McCaffrey's Dragonriders of Pern series. Tolkien stated that his fantasy stories were meant to have actually occurred in our world, during a lost historical era roughly six thousand years ago; Tolkien's authorial conceit was that he simply found and "translated" a copy of the saga, similar to how the Anglo-Saxon saga Beowulf was lost for centuries until it was rediscovered. Meanwhile, McCaffrey's Pern fantasy series is really set in the far future, with the twist being that it's actually a colony planet that regressed to medieval technology levels (and in which dragons do exist, but created by the original colonists through genetic engineering). Similarly, Terry Brooks' Sword of Shannara series or Pendelton Ward's Adventure Time are also set in what appear to be medieval fantasy settings, but actually take place in post-apocalyptic futures after technological human civilization has fallen, allowing magic to come back into the world. Martin, however, has adamantly denied that Westeros is set in either the past or future of real life Earth.
The unnamed world on which Westeros is located experiences erratic and extremely long seasons, which usually last at least several years and have been known to last a decade. It is vaguely implied that this was not always so, as characters still refer to a "year" as a twelve month period, etc. Martin has stated that the ultimate cause of these long seasons is magical, and not technological (unlike the Pern series, which ultimately revealed scientific or technological explanations to seemingly magical phenomena in the story).
Most of the storyline is centered in the continent of Westeros, thus the worldview given to the audience is only the narrow perspective of the medieval population living there. Their society has not explored and mapped out the entire world. Much of the eastern continent of Essos is known fairly well to them through trade contact, but even so, the edges of their maps are simply blank space waiting to be filled in. George R.R. Martin has stated that his medieval fantasy world is based on specifically medieval Europe, thus most of the continents and inhabitants are loosely analogous to Europe in the Middle Ages.
The basic conceit of the setting is, "what if the British Isles were the size of South America?" to the point of being a continent unto themselves. Martin has stated that the continent of Westeros is specifically based on an over-sized British Isles, and that it is roughly the size of South America. The "Seven Kingdoms" of Westeros are loosely analogous to the Anglo-Saxon Heptarchy, the seven Anglo-Saxon kingdoms which they established in the British Isles after their invasion. The North is intended to be loosely analogous to Scotland. Just as the Anglo-Saxons invaded the Celtic inhabitants of Britain, the Andals invaded the First Men who lived in Westeros. Centuries later, the Andals were themselves conquered by the Targaryens, in a loose equivalent of the Norman Conquest. Essos is loosely based on Eurasia: it was once dominated by Valyria, their equivalent of the Roman Republic, which fell several hundred years ago. Valyria's surviving colonies went on to become the Free Cities, which share several features with medieval Italy or other medieval urban areas in Western Europe. The Dothraki from the central-eastern plains of Essos are loosely based on steppe nomads such as the Mongols (with some additional elements of Amerindian plains peoples). Qarth is somewhat like Constantinople or India, though Martin has said that racially the pale white Qartheen aren't based on any real life group. Yi Ti, even further east than Qarth, is analogous to Imperial China and the Far East. Sothoryos is analogous to Africa, but just as Western Europe did not possess much knowledge of Africa or East Asia in the Middle Ages, neither do people in Westeros. The audience shares the perspective of the characters, because of Martin's narration (shifting third-person limited) style, and thus we only know what they know. It's a thematic point that the lands north of the Wall are unexplored and poorly mapped, just as they would be to a Roman soldier standing on Hadrian's Wall looking north to the edge of the known world. Martin has stated that he therefore will never reveal an omniscient map of the entire world his stories take place in:
- "I'm sorry, but if there's an Antarctica in [the same world as] Westeros, you're going to have to wait to find out about it, and/or Australia, and the Americas, and all of that. This is just sort of Europe: a super-Europe/super-Asia [Essos], and a giant British Isles [Westeros], and, you know, like they would have actually known in the Middle Ages."
Also, Martin has stressed that it should not be assumed that his fantasy world even has an equivalent to the Americas or Australia, just waiting to be discovered. They might simply not exist, or have no direct analogues.
If the analogous situation holds that Westeros is their word's equivalent to the British Isles, Yi Ti is the equivalent to China, and only the north coasts of Sothoryos have been explored, this would mean that only less than a fourth of the entire globe is known to men living in Westros (the northern half of their eastern hemisphere above their equator).
Martin has also stated that the storyline in his books is partially (and loosely) inspired by the War of the Roses, the civil war that occurred in England in the late 1400s following its defeat in the Hundred Years' War. Just as the War of the Roses was fought between the Yorks and Lancasters, the conflict in Game of Thrones is between the Starks and Lannisters. The technology level in their society more or less matches Late Medieval Europe, i.e. right before the use of gunpowder and cannons revolutionized medieval warfare and brought it into the Early Modern era.
In the books
In the A Song of Ice and Fire novels, the world is presented much as in the series, although information about it was revealed much more slowly. No map of Essos existed at all until the publication of A Storm of Swords in 2000, which featured a map of Slaver's Bay. A Dance with Dragons added a map of the Free Cities in 2011 (after Season 1 aired). No map of the world beyond Westeros was provided during Season 1 of the TV series, through the HBO Viewer's Guide or other official supplementary materials. The opening credits only briefly depicted Pentos and Vaes Dothrak in such a way as to make their surrounding geography vague.
HBO then released a larger world map on their website in 2012 when Season 2 began airing, based an early draft map of these eastern lands that George R.R. Martin provided them. However, Martin subsequently changed his conception of much of the eastern part of the world (roughly from east of the Dothraki Sea and the Red Waste, including Qarth and all the Jade Sea) subsequent to HBO creating their own map. The new, canon-for-the-books world map first appeared in The Lands of Ice and Fire, published in late 2012.
The Lands of Ice and Fire revealed that Vaes Dothrak is in the northeast corner of the Dothraki Sea, and Qarth is roughly straight south from it along the same line of longitude, though on the opposite side of Essos. East of both Vaes Dothrak and Qarth are the largest mountain chain in the known world, the massive Bone Mountains, which form a nearly impenetrable spine stretching from the southern coast to the northern coast of the continent. There are only a few passes between the Bone Mountains, forming a major barrier for west-east travel. Thus "everything east of the Bone Mountains" and "everything east of the Dothraki Sea and Qarth" are interchangeable phrases. Knowledge of lands east of this clearly defined dividing line is very limited, though the maesters of the Citadel do have a rough map of it. The lands around the Jade Sea are in contact with Qarth through regular sea trade routes, such as the great empire of Yi Ti. Asshai is located at the far eastern edge of the Jade Sea and is little visited, due to its ill repute.
The major difference between the early-draft map that HBO has been using for the TV series since Season 2 and Martin's finalized map in The Lands of Ice and Fire is that the Jade Sea curves to the north in the early draft, but it curves sharply to the south in the final draft. Yi Ti is located on the northern coast of the Jade Sea, so the early draft map that HBO uses places it at a much more northerly latitude than in Martin's final draft version. This would substantially alter Yi Ti's climate, which is actually sub-tropical in the final draft map. In the final draft, the Hyrkoonian cities of Bayasabhad, Shamyriana, and Kayakayanaya are oasis-cities in vast rain-shadow desert on the eastern shoulders of the Bone Mountains. In contrast, the early-draft HBO map depicts them as port cities on the coast of the Jade Sea, west of Yi Ti.
Martin himself explained the discrepancy:
- I had some very early primitive maps about what's on the other side of Qarth, and I gave those maps to HBO at a certain point, and HBO started issuing maps, which used those maps. But when I was doing the map book, I looked at those maps, and said, 'eh, this doesn't work, I don't like this, I don't like the way it's working out', so I completely threw those out, and I redesigned everything east of Qarth into something I like a lot better. So the HBO Game of Thrones world is significantly different from the A Song of Ice and Fire world, in even its basic geography, because of that change.
Ever since the break between Season 2 and Season 3, therefore, it has been unclear if the HBO world map would be updated to the Lands of Ice and Fire book-canon world map. As of the end of Season 5, it has not been updated.
This has virtually no impact on the narrative within the TV series itself, because the Dothraki Sea and Qarth are the farthest east that the narrative has ever gone, and hardly anything east of those locations has even been mentioned in the TV series. Barely anything was known about them from the core novels themselves, just from subsequent sourcebooks such as The Lands of Ice and Fire or the World of Ice and Fire 2014 sourcebook.
The official TV maps have also curiously left out the Summer Islands, Naath, and Sothoryos. These locations do clearly appear in the opening credits sequence, however - from Seasons 3 to 4 onward - just not in official HBO guide maps. Naath and Sothoryos appear where they do in the books and in accurate detail - given that they first appeared in the "Map of Slaver's Bay" and its surrounding first released with the third novel in 2000. Prior to Seasons 1 and 2, the novels already gave the general indication that the Summer Islands are south of the Narrow Sea (southeast of Westeros and southwest of Essos), but west of Sothoryos. Because the TV series already had this information, the appearance of the Summer Islands in the Season 3-4 opening credits generally matches this - but an official map of the Summer Islands was not released until The Lands of Ice and Fire, so their brief appearance in the opening credits is often at the edge of the map, and more vaguely representational. This is not a "change", so much as the TV series has simply avoided using the official map detail of the Summer Islands from The Lands of Ice and Fire.
The Lands of Ice and Fire also mentions the existence of another large landmass south of Asshai and east of Sothoryos, called "Ulthos". It is explicitly unclear to characters in the narrative if Ulthos is a separate, fourth continent, or simply a very large island or subsection of Essos or Sothoryos. Even Asshai is shrouded in legend to people in Westeros, and they have heard nothing of "Ulthos" other than the name in accounts about Asshai's geography - emphasizing that there are blank corners of the map that have not yet been explored by people from Westeros.
Even the world map appearing in The Lands of Ice and Fire, however, only depicts a map of "the known world" as it would be known to educated men in Westeros, such as the Maesters of the Citadel. Thus it is reasonably accurate for regions of the eastern continents which are well-known to Westeros through trade contact (the Free Cities, Valyria, Slaver's Bay, etc.) but in the extreme far east near distant Asshai, myths and legends cloud the facts, resulting in descriptions of cannibals, "bloodless men", and "winged men" on the map which should not be accepted by the reader as objectively true. As George R.R. Martin himself explains:
- "I like my readers to see my world as my characters see it. And the truth is, medieval maps were not very good, by modern standards. A map drawn by an Englishman in 1300 might be fairly accurate for England and maybe France, but distortions and errors would start creeping in when you got to Italy and Germany, the Russias and the Holy Land would be more distorted still, Africa was largely unknown below the Sahara (even the coasts), and further east you started getting "the realm of Prester John" and "land of the two-headed men" and "here there be dragons."...You will find a map of the "known world" in The Lands of Ice and Fire...Even so, it's not a complete world map, no. The idea was to do something representing the lands and seas of which, say, a maester of the Citadel might be aware... and while the maesters know more about Asshai and the lands beyond than a medieval monk knew about Cathay [China], distance remains a factor, and past a certain point legends and myths will creep in. Here there be winged men, and such."
Jonathan Roberts, the professional illustrator who drew the maps used in The Lands of Ice and Fire based on Martin's instructions, was asked about the discrepancy between the TV map (based on earlier drafts) and the now-canon world map for the books he drew, which are different east of the Dothraki and Qarth. Roberts offered his unofficial opinion that it isn't really an "inconsistency", because again, the world map he drew is intended to be a map written by educated people in Westeros, and their knowledge about semi-mythical lands of the very far east is simply inaccurate to begin with (such as real-life maps produced in Medieval Europe that got the geography of China completely wrong). Thus neither the map the TV series was using nor his map can really be said to be an "accurate" map of Yi Ti and the regions of the Farther East.
- Known world on A Wiki of Ice and Fire
- Astronomy on A Wiki of Ice and Fire
- Far-eye on A Wiki of Ice and Fire