BULLSEYE!
So Ishgard was founded about a thousand years ago, Limsa was founded seven hundred years ago, Gridania was founded five-something years ago (my bet is on hundreds, since thousands would be far too Allagan by my reckoning), and only Ul'dah remains without a date.
That's at least three out of six cities founded after the last appearance of the Grand Companies of Eorzea.
Yet the foundation day events spoke of the "reformation" of the grand companies, not simply their inception.

Originally Posted by
The Harbor Herald
Change is afoot in Limsa Lominsa, and blind is the sailor who has failed to notice. While it is true that our city-state’s wharves are inherently dynamic places, ever-vibrant with the coming and going of vessels, folk, and freight, the changes of which I speak fall not into the daily norm.
The dragon galley has launched—the sleek, black craft on a field of red that is the ensign of the Maelstrom, Limsa Lominsa’s recently revived Grand Company. Pennants bearing the oared dragon now snap and ripple across the city-state, raised at the behest of our military’s brass hats. Their purpose: to kindle citizen morale. It would appear that our leaders have forgotten that Limsa Lominsa is a port of freemen. Did it not occur to them that such an overt display of jingoism would sooner wake a spirit of defiance within hot-blooded sailors than instill them with a sense of unity?
What in the seven hells is going on here!?!?