Before starting with each of the regions' explanation of how they ended up there, let me explain another concept od this theory that could be possible:
THE FOG
In this context, the fog would be the force that moves the things that go missing from a world to the Super 4 one. In the episode "Fog Over Kingsland" (which is also one of the few ones with lore consistency, due to Sir Alph caring about Ruby specifically, which could connect to the events in "Ruby, Queen of the Seas"), the people deeply fear the fog. It could just be pure instinct, but it could also be the memory of the day that they got teleported into the world they live in today. In this case, it'd be a blurry memory, since they're not supposed to actually remember anything from the world they belonged to in the past. Now, let's take a look at the official map and get actually started with Medievalia:
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First off, we can see that it's the biggest chunk of land, having as much as three different parts to it (Kingsland, the Baron's domain and dragon territory). And keep in mind that people from those ages (especially if they belonged to the castle) were absolutely IN LOVE with conquering territories (we also know they like it in this universe as well since the Baron is a sucker for political power). However, how long would it take to conquer that much?
Also notice how Enchanted Island and Medievalia are the only ones without fog (even tho Gunpowder Island's is coming from the Volcano, but I'll explain that detail when I make its dedicated chapter). Technopolis and Gunpowder were never shown to have fog around them. So my guess is that the people of Medievalia witnessed the appearance of both those places (not the Lost World since its fog is natural, and, since it's got dinosaurs, it's probably the oldest land) and put that into their map.
Besides, in the chapter "Fog Over Kingsland", king Kendrick says this:
What does this have to do with anything? Well, first of all, it confirms that Kingsland is 1231 years old minimum, since you know, there's only one spring per year and the tournament is held once every spring, therefore every year. That could be proof that Medievalia is the second oldest land (right after The Lost World). It would also make sense with Earth's timeline: knights came waaay before pirates (especially ones that look like they're from the 17th-18th century, though Ruby looks more like people in the 19th century, keep that little difference in mind!!) and advanced technology such as Technopolis'.
Well that was long! As always, any additions or corrections to what I've written here are welcome! Please comment which land you'd like to hear about next, I'm already working on Technopolis but I'll gladly take any requests (and any juicy lore-related information you want to share, I really don't want to rewatch the whole two seasons in one go...)
