Wasn’t Hearts Warming Eve set BEFORE Celestia/Luna’s dominance? When unicorns controlled the Sun and Moon? If that’s so, it occurred long before King Sombra. I can’t see Princess Platinum as his daughter.
I consider the “Ancient Events” to have happened in rapid Succession. On a specific timeline.
First the known leaders ran off to found Equestria. That is the earliest point we have.
Second Celestia and Luna show up. No Elements Yet.
They Defeat Sombra, without the Elements. (Did You see them use the elements in the flash back? I Didn’t!)
Discord shows up.
Celestia and Luna Discover the Elements.
Defeat of Discord.
Luna goes Nuts.
Now if that Timeline is Right, and the events are as close together as I think they are due to the evidence of Star-swirl the bearded being alive both before the founding of Equestria and up to the defeat of Discord. Then it makes perfect sense that Both Princess Platinum and her Father the Unicorn King could even have still been Alive by the time Celestia and Luna Showed up. As Not Even One Elderly Pony Had Died Yet!
Oh, and if you doubt my claim of Star-Swirl being Alive at those times; The fact is, he was mentioned in the Hearth’s warming Story by Clover the Clever first of all, and Second, I’m Going to have to put a spoiler on this next bit of information because:
Discord is actually Star-Swirl The Bearded! And assuming he was only long lived because he became discord, or even because he was turned to stone. Then As you can see clearly already detailed above, not even a single lifetime had passed between Equestria’s founding and all the other major events of “A thousand years ago”!
At this point, I’m beginning to think all these mentions of the phrase “A thousand Years ago” means that Literally, all these thousand Year ago events took place over the span of a single year or two! All of them! Heck, I’d be willing to bet that “One Thousand Years ago” is actually the exact amount of years ago all these events were… Each and every time!
Edit:
Now that I’ve finished one Theory, Here’s another I want to pose the possibility of… But seems to have full room to move.
We haven’t figured out how Pony Maturation and Growth works yet, some Ponies are tall and or long, others large, some appear to be the same size as the main six when Adult, and then there’s Alicorns.
That does raise a question. What if “Adulthood” and “Fully Grown” don’t necessarily seem to be the same thing? What if some sections of ponies continue growing well past adulthood?
And What about Alicorns? Considering Twilight might become an Alicorn, Emphasis on MIGHT! Then one does begin to wonder, after all, “Filly Cadence” did look to be just a little bigger than a regular pony. Making me wonder if there would be like a second growth Phase that continues on from pony, accounting for a fully grown Alicorn’s Size.
Of course, Alicorn Maturity is pretty strange in itself. As Luna seems to go forward and back as her strength wanes. And since some have pondered the significance of a thousand years disappeared Crystal Pony Saying “The Crystal Princess has returned”, when Cadence was a filly when We saw her in flashback. It could suggest Cyclic Maturation Cycles From Full grown to young and back. But then again That explains jack all about how Cadence knows jack all about her kingdom. Unless you take into account that she may have genuinely been a filly when it disappeared and knew jack all, but came to defend it cause she remembered being there at least. Who knows?