Now I want to check just how deep... okay, in our world, recorded history begins around 5500 years ago, with the development of Cuneiform and Hieroyglyphics. There are forms of 'proto-writing' going back to ca. 8500 years ago, so you could argue that people might have been recording history at that point. That's also around the end of the Neolithic and the development of metalworking as a widespread technology, and around the time civilisation of some kind began in Egypt. The oldest surviving structure in the world (a tomb in France) would not be built for another two thousand years.
In the Levant, the first walls of Jericho were being built - the very first walled city in history. The first settlement in Jericho was another 3000 years earlier, 11 000 years ago. It's the oldest settlement we know of that is still inhabited today.
Push back another thousand years or so, and you're at the invention of agriculture and the start of the Neolithic. Before this point, humanity existed as hunter-gatherers in the Paleolithic (Old Stone Age).
15 000 years ago, the last ice age (roughly) ended. The earliest cave paintings date to 44 000 years ago. Major modern human expansion out of Africa started about 50 000 years ago - that's how far you've gone back. Like I said, holy heck.
But you said 'beginning hundreds' - plural - 'of thousand years before', so let's keep going:
The last ice age began some 115 000 years ago. Homo sapiens only started leaving Africa 200 000 to 100 000 years ago. Heck, H. sap only evolved some 300 000 years ago.
That's a really really long time. By comparison, Tolkien's timelines (inasmuch as they exist in coherent form) show that Middle-earth itself is only 55 000 years old by the time of the War of the Ring, and the oldest incarnates - the Elves - date back a mere 11 000.
I have to ask: how have you kept a society static on an evolutionary timescale? In particular, I'm fascinated that you seem to have held it at a medieval-esque point. I can just about imagine a static magical 'hunter-gatherer' society - if you can literally magic up food, there's no incentive to invent agriculture at all - but you seem to be talking about a city-dwelling people. So - without trying to pressure you into revealing plot details you don't want to - I really want to know how. ^_^