Just from the summary I'm definitely gonna look foward to this, ima wait till it has a few more chapters to read, but im definitely following this

Gonna be honest, I'm having a bit of trouble with following the time scale here.

Spoilering so it doesn't give away information before people read it.

A millennium is 1,000 years, so half a millenium would be 500 years. Dragons, at least in common lore, can live to be several thousand years or more.
with a Decade being only 10 years, the 8 decade time skip is only 80 years. A dragon attack would've been well within recent memory for at least a generation or two if we assume ponies have a lifespan similar to humans. Though a lot of speculation has put the average pony lifespan to be much longer since Granny Smith was around at the founding of Ponyville.

Admittedly, it does have me thinking there might be some kind of cover-up in play if it has only been 80 years... it's also rather odd that Torch wouldn't have told his daughter why this dragon was imprisoned.

11418277
Ah, someone is paying attention.
So a few things. Yeah dragon attacks would be taken into consideration and remembered but i would argue that Celestia is covering it up and the ponies have moved on.
Now yes ponies do have a good lifespan but if they are living near boarders of hostile environments, that number would be shorter.
As for why Torch refused to bring it up... well maybe the chapter will clarify it

11418277
They did mention that the town wasn't in celestias border so in my mind either a cover up or ignorance to what happened. I imagine a lot of regular citizens don't pay much attention to what goes on outside their country

11418353
Yeah, it was just something I had to get out of my system when I saw the logic there. I'm... quite curious.

The title and description caught my intrigue long enough to start reading. And this chapter got my attention, and I'm now really looking forward to seeing future chapters and seeing how the story develops

I hope there is more, good story!

11548011
There will. Check my blogs to see that its been pushed into months of july i think.