I haven't written this up yet.
So far, I've started to write up the cities of Vlydyga and Bianzie.
Other parts of the world may or may not follow thereafter. We'll see how it goes.
Geographically, there are two important continents.
There are six particularly large cities, Ite, Bianzie, Hawa, Spandla, Madon and Norg.
There is only one truly large city on the continent, Vlydyga.
Other locations which I shall probably add in due course are the isolated city of Juinden-Muilly and the equally isolated Castle of Foletercheduastry, (because they are the homes of important and widely-travelled NPCs who might crop up anywhere).
The name of the world is Wregin; the principal language of the Main Continent is Wregnish and natives of the world are known as Wregniards. Hopefully, this will confuse the players into thinking that there is some connection between Wregin and Spain. There isn't.
I know nothing about the Wregnish language other than that nouns ending in vowels are feminine and nouns ending in consonants are masculine. I know nothing at all about the Wregnish writing system (although obviously they have one), as I've never got around to inventing one. If it becomes important, make it up.
Wregin has a moon, and it's inordinately large. I'll write more about this in due course.
Humans did not originate on Wregin and have not yet adapted to it fully. Humans arrived on the world less than two thousand years ago. No-one seriously doubts this, as there is plenty of evidence around to support the fact. Dwarves and orcs are similarly not indigenous, but have lived on the world for considerably longer than humans. It is generally believed that elves are indigenous, but the evidence for this is inconclusive.
In the old days, a century or two ago, people knew where they were. Religion was simple. Civilisation honoured the Preserver, a lawful neutral deity, by whatever name that deity chose to be known by in a particular city. Druids honoured the Creator, a neutral deity, but they did so outside the cities because the priests of the Preserver didn't want any creating going on inside the city walls. Those people who insisted on honouring the Destroyer, a chaotic evil deity, were exiled to the dark, dismal city of Vlydyga on the rear continent.
Nowadays, things are confused. The priests of the Preserver still nominally rule in the six cities, but Vlydyga is no longer dark and dismal and is fast becoming a popular tourist trap.
Important religious note: The old trinity of indigenous Wregnish deities are worried about the influx of foreign religions. This is a problem all over the world, but particularly in Vlydyga, where the tourists have been accompanied by missionaries.
[AD&D-specific] In an attempt to counter this, the Preserver, the Creator or the Destroyer allow any native-born Wregniard of any alignment other than chaotic good to ask one of them for, and generally receive, low-level clerical spells (this applies to humans, orcs, half-orcs, half-elves and dwarves, but not to elves). Most native-born Wregniards do this. The spells awarded will typically be one 1st-level spell plus any which the person would be entitled to by virtue of high wisdom/intuition. The spells awarded are decided by the deity in question, and since their purpose is to improve the quality of life of normal citizens (and to retain their loyalty) they will typically not be all that useful to adventurers.
Some possibilities are:
It follows that pious people of lawful alignment will have clean, tidy homes, without having to put much effort into maintaining them. That's the way religion ought to work.