the Cylon Centurions, they proposed an exchange of technology to accelerate the transformation of the new race of Cylons into biological forms and resurrection technology; additionally, they shared their history and religious knowledge, though did not interfere with the Centurians' emerging monotheism, ensuring that newer Cylons had knowledge of both. The Centurions agreed and ended the war with humanity, retreating to rebuild and learn from the final five, eventually building and programming the humanoid Cylons which were each given a production number: One (Cavil), Two (Leoben), Three (D'Anna), Four (Simon), Five (Aaron), Six (Caprica), Seven (Daniel) and Eight (Sharon). Over time, Cavil gained influence and betrayed his creators, the "final five". He killed their physical bodies and "boxed" their personalities. Later he resurrected them periodically, purged their memories and sent them to live among the humans, hoping each would become disillusioned with being "human" and eventually reject the morality, philosophy, and religion used to inform their construction of the younger Cylons. The other six models had no knowledge of the Final Five's identities, presumably blocked by Cavil, though they were aware of the existence of five absent models who were not to be spoken of. When D'Anna (a Three) attempts to learn their identities, Cavil boxes her entire model line as punishment. In the final episode of the third season, four of the final five are revealed to be characters with long histories on the Galactica. Their purpose, and how and why they were hidden from the rest of their kind, is a major plot point of the fourth and final season when Ellen Tigh is revealed to be the fifth member. Backstory The named, "human", Cylon models initially refer to the five with reverence; it soon become clear that they are programmed to avoid thinking directly about the five, as their identities are hidden, even from Cylons. Circumventing this programming kills a model three shortly after her revelation, and a model one, Cavil, puts her consciousness into cold storage after resurrection to prevent her from discussing the discovery ("Rapture"). They were the original humanoid Cylons, born 2,000 years before the series, on Earth, as part of the Thirteenth Tribe. They were born to Cylon parents through sexual reproduction, rather than built. They were the researchers who rebuilt the Cylon resurrection technology that had been abandoned when the Thirteenth Tribe gained the ability to procreate. Saul and Ellen were married