Cylon

The History Of The Cylons In The Re-Imagined Series (Warning: Big spoilers):

The First Cylons:

   The first Cylons were originally created several thousand years ago by the 12 tribes of humans on the planet Kobol. It is unknown what form the cylons took at the time of their creation, however, we know that they eventually evolved into a humanoid form. These humanoid Cylons were near indistinguishable from humans, and even had the ability to procreate. These Cylons became known as the thirteenth tribe of Kobol. Very little is known about Cylon life on Kobol, but it's assumed it was a time of high technology, because of the nature of their creation as artificial lifeforms, as well as their known ability to resurrect themselves after death into new bodies. For reasons unknown, the Cylons departed their fellow tribes and eventually colonized a planet that would be known as Earth. (It's worth noting that the thirteenth tribe was not the only one to leave Kobol, 2000 years later the other 12 tribes would depart Kobol and form colonies on planets of their own.)

Cylon Life On Earth:

   Not much is known about Cylon life on earth. It's known that they lost a relatively large amount of their technology in their exodus from Kobol, including the ability to resurrect themselves, however it is known that Cylon researchers eventually rediscovered this technology. The Cylons seemed to lead relatively similar lives to that of Humans today, lives that included such cultural values as Music.

The Cylon Holocaust:

   Some 2000 years after leaving Kobol and settling on Earth, the Cylons were victim to a massive Tragedy. The planet was completely engulfed in the flames of nuclear weapons. Fans of the series theorize that the Cylons created another generation of artificial life of their own, and that the "Cylons" that they created eventually rebelled against them. The destruction of earth took place around the same time as the exodus of the 12 other tribes back on Kobol, because of this, some believe the two are connected.  Earth was left in total ruin and the Cylon race was all but eradicated.

The Final Five and Their Escape:

A group of 5 Cylon researchers (Who would later be known in the series as The Final Five) who had worked on rediscovering Cylon ressurection somehow foresaw the attack was coming. Because of the researchers' prior knowledge of the attack they were able to make sure that they ressurected aboard a station in orbit around Earth and were safe from nuclear fire. The 5 researchers then set out to warn the other colonies of attack, assuming that they too would create artificial life that would eventually turn against them. Because their people hadn't developed jump drives the Five's ship traveled at relativistic, but subluminal speed. Time slowed down for them, but thousands of years would pass before they reached the other Colonies.

Cylon Creation On The Other 12 Colonies and The First Cylon War:

   Around the same time of the Cylon destruction of the earth, the other 12 tribes on Kobol (All of which were human) left Kobol and each colonized a planet. For 2000 years the people of these colonies developed and thrived, and a central goverment was formed. Eventually however, just as The FInal Five predicted, the humans redeveloped Cylons to assist with labor throughout the 12 colonies. These Cylons hadn't yet evolved to the same extent that the Cylons who colonized Earth did, and as such were crudely designed walking robots. The Cylons were treated like slaves by the humans, and again, just as a the Five had predicted, these Cylons eventually rebelled against their human masters, resulting in what be known as the first Cylon war. The Cylons apparently had developed enough to have their own ships and infrastructure, making them a formidable foe.

The Five's Arrival At The Colonies and The Creation Of The New Humanoid Cylons:

    The Final Five Cylons finally arrived at the 12 colonies during the first Cylon war, around 2000 years after they departed Earth. They then realized they were too late to warn the other tribes. They were astonished to find that the Cylons (known as the Centurions) believed in a single loving god, they believed they could end the cycle of violence because of this, so they made a deal with the Cylons. The Centurions had already been trying to create flesh bodies, but they failed to make anything that could live on its own, so In exchange for ending the war with the humans, the FInal Five would create 8 more humanoid models of Cylon for them, each being aesthetically the same as a human. Each of these new humanoid Cylons had their own personalities, but were mass produced, with each model able to share a single bank of memories, each model assigned a number for identification. These Cylons were not exactly like the Cylons of earth, for example, they lost the ability to procreate. The first of these models would be known as John, also known as "Cavil", or "Number One" in the series. John had a hatred toward humans for treating the Centurions like slaves, and was generally an evil and twisted being. Because of John's jealous and sadistic nature, he would later destroy the entire Number Seven line in jealousy.

The Second Cylon War and The Eradication Of The Colonies:

   Sometime in the 40 years after the Final Five made a deal with the Cylons and ended the first Cylon war, conflict once again sparked in the Cylon infrastructure. Because of his twisted nature, John (Number One) lead the other 6 cylon models against the Final Five and imprisoned them for their friendly feelings toward the humans. Boxing their personalities away in a storage bank, and made plans to wipe out the humans of the twelve colonies. Eventually John unboxed their personalities and set the Five loose into the colonies, erasing their memories and making them believe they were human. He hoped that once they died and resurrected on a Cylon ship, therefore regaining their memories, they would realize the nature of humans and side with him against them.

40 years after the first Cylon war ended, the new Cylon infrastructure infiltrated the colonies defense mainframe through manipulation of a man named Gaius Baltar. After crippling their defenses, the Cylons launched an all out surprise nuclear offensive and wiped out what was almost the entire human race. The Final Five all survived this attack and ended up being a part of the fleet of 50,298 human survivors.