At a certain depth, history is no longer passive. It infects. It waits in the dark for the foolish to stumble upon it. Whatever the elders told you, ignorance is not the resting state of the human mind, it is a defense mechanism, a mental martial art honed by generations in order to forget histories of madness and exploitation, the kind of trauma that scars the faces of worlds.
(Each variable has ~40 results, but the table only chooses from 12 of them. The number of "centuries ago" modifies which set of 12 results the table chooses from, making it seem like history is moving through different periods with their own themes. The limit is ~40 centuries in, where it'll start giving you a pre-creation response message.)