The basics of my world were inspired by maps. I have loved the way some names sounded.
The first kingdom I created was Akkad, its king, Sargon, of course. Caledonia became Kalydon and all the artifact creators in the 1e DMG were involved in it in some fashion. The Mighty Servant of Leuk-o destroyed a forest sacred to the female druidic goddess, for instance. Other names were Cymru, Mantua and Padua, Kesh, Zimbabwe, Punt, Sheba, Phalia and Westphalia, Phrygia and Cathay. They helped me set out what kinds of cultures were there. this meant I could run just about anything I could ever think of in my world.
I meant for the fall of Kalydon to explain why there were so many magical doodads scattered all across the world. The armies of Kalydon were all issued magical armor and weapons. The artifacts were created because Kalydon enjoyed the use of spells greater than 9th level. The Empire conquered most of the known world that way. The Fall of Magic, a mystical calamity, caused most of the magic to fail, or be twisted. The Empire collapsed because it was too large to be controlled without magic and there were only up to level 9 spells available now. As the retreating armies were destroyed the remaining items were lost and scattered.
I wanted a powerful monotheistic church to play around with intrigues and such. I made the Church of Our Lady of the One True Way (OLotOTW) and allowed clerics to be of any alignment except for N/N. there were two druidic faiths, the northern one was celtic with a male god and the southern was a kind of Ki/Meilikki mix. the Church of OLotOTW was trying to suppress the northern faith as they felt it would be easier to incorporate the female goddess as an aspect of Our Lady. naturally, all the PCs followed the celtic style druids, at least at the beginning, snce that was what they were most used to. It was a player who instigated two Crusades versus orcs and an Inquisition that was a bit unfocused but annoying to most of the other players.
I also used Lovecraftian references, the Plateau of Leng collapsed at the time of the Fall of Magic and created the Shallow Sea, filled with pirates and odd fishmen that made the central sea dangerous. This meant that trade always skirted the coast in that region and only the bravest avoided having to deal with various nations. Were you bothered more by the unknown or taxes? that determined where you sailed.
Because I dislike psionics the Empire took precautions from invasion by 'other-worldly' beings with tentacled faces and odd dietary habits. there were odd shaped stones and ancient runes involved.... and all of it written down in private journals handed down within families for hundreds of generations.
Inspired by Lieber, I ran an adventure where a castle was enchanted by a group of enchanted gems, and was nearly alive because of it. it sat atop a maze of caverns that led to other dimensions in addition to the Underdark. It became the party's base of operations for over a decade of gaming.
I also chose to add draconians to my dragon kingdoms, but obviously altered the storyline to blame the Empire or those who had fallen from it. In the Monster Manual, any reference to creatures beginnings involving 'insane godlings', 'evil spellcasters' or 'foul researches' were all attributed to the Emperor, the Empire and those working for it.
"Maps encourage boldness. They're like cryptic love letters. They make anything seem possible." Mark Jenkins, "To Timbuktu"
there was another quote about a man who likes maps that was on a painting but can't find it right now.
If ever in search of a cool name for a place look in an Atlas of History and you should be able to find something.
