Can you have several independent kingdoms which share the same culture, language and religion?

it always baffles me how artists seem unable to understand how the tip of a sword was shaped.....

Of course you can, dumbass.

If they just recently split from each other then sure.

Aye, but that's not exactly sharing a culture?
It's a continuum, you're not wrong, but there are definable differences between someone from Land's End and someone from John O'Groats whether it's circa 1200 or nowadays.
It really depends on how you define culture though.

Sure. If you feel the need to explicitly hang a lantern on it, say that not too long ago the whole region was part of a much larger empire that has since collapsed. The religion, culture, and language all remain from when they were a unified empire, and since trade between neighboring kingdoms remains they have not diverged all that heavily yet.

I was
I could justifiably claim Bradford has a different culture to Leeds. Different recent histories, different industrial specialisation, different economic growth, different dialectal terms for certain things.
These things could all be used to build a case for them being different, but the similarities they share are huge. Cornwall and Aberdeen shire are still more alike than say Spain and France. I also want to clarify, when I say Britain I mean the island of Britain, just England Wales and Scotland.

Of course, it helps if there is some irreconcilable difference or other barrier to unification, just to explain why the monarchs wouldn't just wed their kids together and establish a new Empire.

>>I could justifiably claim Bradford has a different culture to Leeds
It fucking does now

Kingdoms are not nations. They are just wathever piece of land is controled by this oranother dynasty. Sovereign state didnt appear until the peace of Whestphallia while nationalism didnt appear until the French Revolution.

Rome was too big to rule. Bad rulers and outside pressure put the final nails in the coffin, but the technology of the time made it inevitable that Rome was going to fall apart. They bought some time by delegating power to local rulers and generals, but the Roman Empire was simply too much ground to keep without faster forms of communication and transportation.

...

>Old Russia during its worst times
Yes

Dal Riata stronk! THE PICTISH HEATHEN FELL!

Also Dalriada was on the west coast of Scotland and the east coast of Ulster, not southern scotland. Even then, it didn't exist in 896

See the HRE, the greek city-state, the Italian city-state.

In all those cases you gotta remember that culture is fractal. Like to a Persian the Greeks would have all been the same stubborn barbarians, but to the Greeks lineage was important and the dialects were quite divergent.

It's like that old saying:
"To foreigners, a Yankee is an American.
To Americans, a Yankee is a Northerner.
To Northerners, a Yankee is an Easterner.
To Easterners, a Yankee is a New Englander.
To New Englanders, a Yankee is a Vermonter.
And in Vermont, a Yankee is somebody who eats pie for breakfast."
Though that's more about exonyms, you get the picture

Yes. Of course. Even needing to asking this question is incredibly ignorant. Read a history book.
Nation states are a new thing. What you are describing was the norm until a hundred years ago.

Depends what you mean by "independent" though.
Like the French counts at least paid lip service to the Capets around the turn of the Millennia, same with the HRE and the emperor.
The one case I can think off the top of my head is the three Jimena brothers ruling thirds of their father's kingdom, though that only lasted a generation.
If you're willing to go farther east I guess the Rus would count too

What is wrong with the tip?

sure just look at modern europe

The border gore! My eyes!

You can't share a culture if you have no culture

Holy roman empire right?

>just to explain why the monarchs wouldn't just wed their kids together and establish a new Empire.
That's not how this works.

That's not how any of this works.

Before the modern period it was common for cultures, languages, and ethnicities to be spread across multiple kingdoms and empires, and conversely for kingdoms and empires to contain many different cultures, languages, and ethnicities. Even in ancient Rome, many people didn't speak Latin, weren't ethnically Latin, and weren't traditionally culturally Roman.

Modern nationalism as we commonly think of it literally didn't exist yet.

>implying modern countries aren't still a smear of cultures, languages and ethnicities

That's true for most, yes. But there was no ideal of the nation-state, and even many multicultural nations today are still dominated by a single culture/ethnicity/language etc. Just look at modern France, which nearly entirely speaks French as opposed to a slew of local languages like Occitan, Breton, Picard, etc.