leftover pizza.
found this interesting over at TWoP [link] :
As someone else pointed out, the Earth holocaust happened around the same time that Kobol's civilization self destructed, or better yet, fled for the 12 colonies.
So here's my thoughts on that: maybe the humans and cylons originated on Kobol. They had a war 3600 years ago that resulted in the Cylon exile, or at least in the exile of the original cylons. The humans were not happy having the cylons be out there, so they sent ships out to track the cylons, and when they found Earth, they blew the shit out of it. But the cylons worried about the possibility, so they created a resurrection hub (there were none before) outside of Earth where a few cylons could download to, as a survival mechanism.
Eventually, the 12 models re-awakened in the hub (their "one true god" perhaps?), and were tasked with deciding what to do next. Seven of them were out for blood, whereas five wanted to seek out the humans, to make peace with them, and maybe to live with them again. The five lost the vote, and refused to go with the others. They struck their own path, and the seven were so pissed about it that they agreed to deny their existence by erasing their own memories, not just of the five, but of having lived on Earth for good measure. The seven traveled to Kobol with the non-human models, to lay siege to the planet.
The humans decided they had no choice but to become exiles themselves. The seven were pissed, but decided they would hunt the humans for as long as it took. So they worked on resurrection technology so powerful that it could span most of the universe, so they could hunt the humans forever if that's what was called.
The humans hid their tracks for many centuries, but there was a problem. Feeling shame over what had transpired, perhaps recognizing the error of their ways, they created a whole cover story about a lost colony, and how a cataclysm had caused their diaspora. Over time they also forgot that they were capable to create machines with self-awareness, who refused to do their bidding. They created a new set of cylons, the new non-human models. Meanwhile the five managed to track down the humans while the cylon war was going on. They decided that it would be too risky to approach the humans in the current climate, so they too elected to erase their own memories, so that they could live alongside the humans without revealing their secret (you can't reveal what you don't know).
The new cylons ran into the seven at the end of the war. This new development led them to leave the humans (with the humans interpreting it as a retreat, whereas the cylons were just regrouping). The seven allied with the non-human models of the 12 colonies. They managed to also create controls to subdue some of the models to their will (the collars that the Baseship Six took off from the Centurions when the remaining six started infighting). 50 years later, they laid siege to the 12 colonies, with their only goal to do the same to the humans as had been done to them on Earth. But 50,000 humans escaped the star system, and several more had survived on Caprica. The seven had not anticipated any of this, and it pissed them off. They also had been focused on revenge so much that they had forgotten how to live (see: not being able to couple and reproduce). They decided to track down the humans and enslave every last survivor, perhaps making them pay by succumbing to a fate worse than death (a.k.a. being experimented on, like Starbuck was on Caprica). Some of the seven (the Sixes, the Sharons) eventually realized all on their own that they needed to move on, to find a new quest. For a while, it was to make peace with the humans. That didn't last, so the Deannas came up with this new obsession to find and reconcile with the Five, which three other models later shared. Perhaps it was because unwittingly enough, following the humans meant retracing their path back to Earth, and (continued...)