Re: Who\'s Been Around Longer?
It was never said specifically, but what you can gather is that the Minbari were space-faring for over 1000 years (1000 years ago was the latest Shadow war in which they were at LEAST space worthy enough to put up a good fight). So Minbari were probably 1200-1400 years in space.
The Centauri of the ones you mentioned were next Id say. Maybe they said it, but you have to assume they were around at least 500 years. CERTAINLY longer than the Narns, since they conquered them, and the Narns only gained space flight and technology AFTER pushing the Centauri off their world.
Humans were last to arrive on the scene. We know this because Narns were apparently JUST recently independent once we got on the scene. Then, once the Earth-Minbari war started, Narns tried to help us out (they were just a tad more experienced than we were).
Of the ones you mentioned that was probably the order. Centaur => Narns => Humans.
Again, never specifically mentioned, but from what happened in the series, that is how it plays out.