Geography
The Known World consists of all three continents: Europe, Asia, and Africa. Rumor exists of a new continent far to the west, which some Danes (or was it Vikings?) have managed to colonize by following the edges of the Ice Cap (navigation is done mainly by sight).
The British Isles:
Erin: Feudal, and on the cusp between Barbarian and Civilized. The Sons and Daughters of Erin are NOT part of the British controlled parts of the Isles. They worship the Celtic Deities, or the Druidic faith.
The northern most parts of Erin are Ireland, fully civilized and with Irish Lords and Knights that pay homage to London. The Southern parts are a bit more wild, but not entirely uncivilized. Usually.
Moving east to the other main island, we have Scotland, Wales, and England. Knights in plate, jousting, downtrodden peasants, the whole package. They worship the New God, mostly. To be fair, there are more than a few peasants that are Druidic, and maybe the occasional Scotsman or Irishman that still cleaves to the Celt Deities, as well.
Northern Europe:
On the mainland, to the North, are the Vikings, Danes, and Fins.
Vikingland is to the north of Daneland, and both are coastal. Both worship the Norse Deities, with some New God worship amongst the Danes.
The Vikings are under-civilized, like to take to their ships and go a-viking for plunder and genetic dispersion. It should be noted, however, that they ARE improving...somewhat. Their armor tops out at Scale Mail.
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The Danes are civilized enough to have actual Knights, and have a warm enough climate that they can farm enough to survive winters without needing to pillage.
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And to the east of both countries lies Finland. The Fins are primitive, but not barbaric. Armor choices tend to match that of druids, but, mostly, by necessity. In fact, it is said that Fins are a magical people, and each one knows at least some magic. This is true. At the very least, they use the Variant Human and take Magic Initiate Druid as their feat. Rangers, Sorcerers (Tempest only) and Druids (Moon, Arctic, or Forest only) are an exception, and need not take the variant. They produce no wizards, clerics, or bards. They don't feel the need to pursue Warlockery. Paladins, while rare, do exist, and are unfailingly Green. They, too, need not take the variant race.
Western, Central, and Eastern Europe:
France is much like Britain, but French, which means, amongst other things, no Celt or Druid worship.
Germany and other parts of central Europe continue in the Knightly vein, and mix Norse and New religions. The farther east one goes, however, the more things tend to go bump in the night. In France and Britain, the problems are the people, but in Eastern Europe on into Rus, Monsters rule the Night. Central Europe is the place where things tend to change from the one to the other. And, yes, that means that sometimes people turn into monsters.
Southern Europe, northern Africa, and the Mediterranean:
More civilized, at least in their opinion, and not feeling the need for heavier armors, especially as so much of their economy is dependent on shipping. Light armor, chain shirts, and the occasional breastplate are the rule.
Spain is mostly New God, and still tends to medium armors over light, for the nobility and their troops.
Greece worships their deities.
Rome worships the Greek Deities with a name change. There is a small town near the capital where worshipers of the New God congregate.
Araby, which is basically a group of countries north of the African Jungle, excluding Egypt, follows an Al Qadim pattern, worshiping a mix of Greek and Egyptian Deities. Armor tends to avoid mail, save for nobles' guards in cities.
Egypt and the Nile Valley tend to light armor, and their own Deities. They also display an unprecedented fondness for Necromancy. Every setting needs an Evil Empire. Egypt is this setting's evil empire.
Deepest Darkest Africa:
The Jungle. Not much is known about it. Feel free to go change that.
Asia:
There are three main countries in Asia:
India: a subcontinent all it's own, largely unknown jungles, but the nearest bits follow the Mediterranean pattern, above, with their own, unknown, deities.
Cathay: East of the Rus are the Mongol Hordes, east of them, Cathay, possibly the largest single country in the world. They have their own deities, unknown to the West
Nippon: The land of the Rising Sun, another island kingdom, this one on the far side of Cathay. They have their own deities, unknown to the West.
Atlantis:
West of the Mediterranean Sea, and a ways into the Atlantic Ocean. Hard to find, as it is out of sight of any other lands.
The people of Atlantis are in the Mediterranean mold, but tend towards more knowledge intensive pursuits. Their Fighters are Eldritch Knights, they produce Wizards rather than Sorcerers (usually), and the RARE Warlock is invariably Tome Pact. They tend towards lighter armors, but you never know.