Worldbuilding is no easy feat. You only know the world you inhabit and if you’re fortunate you may hold that opportunity for a hundred years or so out of the hundreds or thousands of years it took to form your familiar world. There’re innumerable events going on every day which you’re not privy to and much is lost without accessible documentation. Yet if you wish to create a world you have to fill in these gaps with events, peoples, traditions, holidays, occupations, foods and more sprung from your mind. It could take an entire lifetime depending on the level of detail. However, if you don’t have a spare hundred years you could model your fictional world on the real world.
Basing a fictional world on a real one is to a writer what mix-in foods are for a home cook. If you don’t have the time or materials to make everything from scratch it can expedite the process. Some of them are pretty good and from the time you were a kid with a busy mother you found your favorites, your comfort foods which stuck with you into adulthood. Mine is anything set in feudal Japan. Call me superficial but samurai, ninjas, and warlords always piques my interest.
This method sets itself within the “If it ain’t broke don’t fix it” school of storytelling. Templates are there for a reason and for all their faults they at least boil an aspect of stories (usually plot) down to the essentials. If you brainstorm the most generic sounding outline just give a bit to breathe. It helps center the reader in a familiar world where they have intuitive knowledge of major events and figures and influences whilst preventing an overabundance of exposition. “The Roman Empire when split into a tetrarchy under four emperors doesn’t have a stable long-term future? Ya’ don’t say?” You can then surprise the reader after shaping their expectations.
A small twist on a historical setting can go a long way. What if the Napoleonic Wars but with dragons? What if Apollo 11 made contact with aliens? What if the Romans went full-bore with their steam engines instead of abandoning the technology? What if there was no Mathew Perry to open Japan and the Edo period limped along another half century putting the nation in no place to participate in World War Two? Innumerable, imagination sparking paths open up with grand promises of wonder.
Also, it lets you put more attention on other parts of the story. If you’re the type of writer who focuses on personal drama, relationships, the average man, small communities, situational comedy, morality plays, etc., you’ll find comfort that none of these depend utterly on a well thought out fictional world. If you wished to set a story of a person’s selfish need for dominance ruining relationships and a chance at true love then does it really matter if the world can be described as basically Paris or basically Rome? Not to misplace that energy, the characters need to have a place where they can become one of the many and not have the author’s hand so clearly elevate their lives above everything else in existence, perhaps a theater where the couple are but two of the many patrons. Meanwhile, the currency exchange rates at the market down the street can be handwaved without a fleshed-out Excel chart.
The alluring nature of using historical events in your story is also its major pitfall: Lack of effort. That sounds retroactive because if the world blends seamlessly into the background then basing it off historical examples was wise. Yet the same tactic can ring hollow if used ineffectively, the worst reading like a Wikipedia article subjected to find and replace. “And Toses lead the Hews out of the lands of Ygipt…” Plot-wise, what should be avoided, provided it’s not historical fiction, is to copy history beat for beat. If you pick a subject in which the layman has cursory knowledge they’ll sniff out every twist and turn chapters ahead. The counter pick is small a scale, local story. A single commando mission or submarine patrol carries fewer presuppositions towards the plot and can surprise the reader.
It’d also benefit the story to quarrel with which historical events to use in (or as) the story. I like my basically Japan with magic or yokai but does the story I want to tell warrant that setting? If you’re not going to put a lot of effort into a particular part of the story then the temptation is to default to something you think is cool and move on. But if I want to tell a story about cultural shifts and grating differences between younger and older generations then the glacial progress of isolated feudal Japan isn’t the place. The easier experience while brainstorming is to write out a bony outline then search the web or ask somebody if they know of anything that’s happened quite like what you’ve described.
“A people sailing onto far-off lands where they interact with the native population? Well there’s the Nordic settlements in Canada, the Spanish Conquistadors and the Aztecs as well as several Caribbean islands, Christopher Columbus, or if you want a real wide gap look to any British colonization effort and if you want to see the colonial power kicked in the teeth look up the New Zealand Wars.”
Something I had to get over, don’t be intimidated by the worldbuilding in classical literature and mythohistory, it’s in the name after all. Shakespeare had the actual life of Caesar and the fallout after his death to write his play and several others were adapted from earlier plays. There was an actual Trojan War to base the Iliad upon. Heracles’s adventures are based on constellations as are many ancient stories. Not to mention old polytheistic religions with their thousands of characters interacting with each other and leaving their marks upon the world (i.e., crippled, half snake inventor of the chariot Ericthonius being the child of crippled inventor Hephaestus) were built upon one another over millenniums and imported from other religions. A fully fleshed out world spawned from an independent mind is the exception. There’s no shame towards your creative abilities for basing your story off anything nor if someone makes that comparison beyond your intentions.
When you’ve made your alterations to history and find yourself in the weeds as you craft what makes your story its own, just remember to choose the least bad option. It’s terrifying as a writer to start with a perfectly good (real world) plot and fast divert into the unknown. You have to think up every effect a different action will have upon the world. Then what good is the rest of the real-world history you’ve based the story off? You can’t have a character make a different choice only to have the plot be diverted back onto the pre-established tracks because you rob the characters of their freewill. It’s a pivotal moment when you have to abandon the real world and form the story as its own work.
If you go back through history with hindsight a lot of negative decisions and developments won’t make much sense but you have to remember the people then didn’t know all the information you did and were working under every limitation. It might be an easier time writing but never did anyone discard an entire world and remake it in their own image.
“Why didn’t each and every people the Romans tried to concur just band together and fight them from the outset?” They would if they could but they’d have to ignore generations of murders and horrors inflicted upon one another as well as the issue of sharing power and a thousand other influences. Some fought back too late, some became subservient, others turned traitor. They couldn’t choose the one best option so they went with the least bad option.
When it comes time to make a decision consider what’s influencing the world and the characters up to that point and cross off what can’t be done. This makes the choice unideal and therefore difficult. Good. Characters need to be challenged, conflicted and make difficult unideal choices and so do you. This is what makes the story interesting and you a better writer. Don’t hope a perfect solution will magically appear over the horizon and fix everything when you could work to find the least bad one to keep the story going and your hands writing.