Time Abyss: The members of the assorted naturally or artificially immortal species of the modern day still haven’t been around long enough for this – although the Empire contains plenty of people who are older than all Earth’s modern nations, and at least a few who are older than human civilization period. With time, they’ll get there.
A few Living Relics dug out of the archives play it straight, but generally lack continuity.
I’m looking forward to hearing the story of the oldest documented individual still around. I’d imagine they have a lot to say.
The trope’s page lists the minimum age as 5,000.
Still not much of a Time Abyss by either SFnal or local standards. I mean, it’s not as if they just have ancient buildings older than that, they have not-only-still-inhabited-but-in-continuous-use buildings that are older than that… which makes it feel decidedly non-Abyssal, y’know?