The Crystal Empire's origins can be traced back to g1
While many people who joined the pony movement when g4 arrived on the scene seem to shun and or mock the past MLP gens, I find that there's a lot of rich history of worldbuilding amongst the older gens that set the stage for gen 4, and seem to be the origin of many of the places we've seen so far in gen 4.
The creation of Crystal Empire- only seen in g4- I believe was brought about by occurrences in G1, as there are numerous ties to artifacts and landscapes there, both during and after Lavan's reign. In G1, the villain (a lava demon) steals princess ponies' magic to turn himself into a crystal creature, so that he can have enough power to to anything he desired. In doing so, he's able to turn the entire landscape to crystal. (which, oddly enough, isn't reversed, when the ponies defeat him) which likely later became the Crystal Empire
Not to mention that when the magic was drained from the princess' magic wands, they were instructed to take them to The 'heart of ponyland'- a magical talisman (which was actually a giant crystal jewel) far beneath the land's kingdom, and the source from which the Princess ponies' wands draw their power, for the magic to be restored, and Lavan could be defeated. To me, this sounds and looks an awful lot like what came to be known as the Crystal Heart residing within the Crystal Empire.
Location, Location, Location!
The landscape across the generations doesn't seem to have changed much (though they have seem to have undergone some name changes- as things often do, even in our world) In Gen 1, there was a volcano that 3 witches lived on, and they'd often leave it to torment ponies in Dream valley or in Flutter Valley. Looking at the map of g4 Equestria, I think it's a safe bet to assume that the G1 volcano is now called Smokey Mountain, Dream Valley is probably Ponyville, now- as it's right in the shadow of a mountain (Canterlot), and Flutter Valley- which was shown to be through a dark forest. Those Ruins coming out from the forest look similar to the stone structures in the Flutter Valley, come to think of it.
There was a river nearby Flutter Valley (because two witches planned on using the water in it to flood the place and disrupt the Flutter Pony's festival). When Baby Lickety Split ran away from dream Valley (which could now be "Ponyville"), she wound up falling into a rocky gorge, which, I suspect is now "Ghastly Gorge", Reeka and Draggle later seems to be seem in a murky, foggy place with lots of dead trees, which could be the Bogg in the Everfree Forest, which back in g1 was known as Shadow Forest, that the gang had to pass through on the way to Flutter valley. Then after the forest, they has to climb up some steep rock walls in a chasm before they reached the valley (Rambling Rock Ridge?)
Unicornia is mentioned in G4's “Hearth's Warming Eve”, and is shown as an actual location in G3
so is Ponyville (along with in G2)
In “Testing, Testing 123”, a pony by the name and title of “Commander Firefly” is mentioned; presumably the Firefly of G1. (baby Firefly is also, again, seen in the IDW MLP's Micro Comic #8, helping protect Canterlot, in the flashback of Celestia discussing the Lunar rebellion- which was before the Wonderbolts were formed)
Unicornia is mentioned in G4's “Hearth's Warming Eve”, and is shown as an actual location in G3
so is Ponyville (along with in G2)
we also learn that it's not uncommon for a baby pony to have the same name and appearance as its mother (Firefly- baby Firefly/ Hearthrob- baby Hearthrob –--> many ponies in g4 have same names and appearance as past gen ponies. Also, in g4, Pinkie Pie mentions her “Granny Pie”)
In IDW MLP's Micro Comic #8, Celestia introduces some pony fillies and colts to her friend. Amongst these young ponies are baby Surprise, Firefly, and Glory. (within a reasonable timeframe for baby Firefly to be the child of the Firefly in the previous image )
Many seem to think that Alicorns only became a race in addition to the 3 pony types (earth, unicorn, and pegasus) in Generation 4, and though there have been alicorns spotted in the background in several episodes, many dismissed them as animation errors. In the Journal of the Two Sisters, written by Amy Keating Rodgers, though, Luna pretty much confirms that other alicorns (besodes her and Celestia, during their filly years) existed and helped raise them? So other Alicorns that had to have been older than them exist.
Now, what if I said that the alicorn race existed even before G4?
Take a look at Gen 2, My Little Pony Tales. In the episode "Up, Up, and Away", the earth ponies think they see a UFO, which actually turns out to be the Glow n' Show Ponies, one of which is Dazzleglow, an Alicorn.