The Cylon Centurion Model 0005 (henceforth referred to as "Centurions") appeared some years prior to the first Cylon War, during which time they were used by Humanity to make life easier on the Twelve Colonies (Miniseries). Unbeknown to the survivors of the second Cylon attack, the Centurions practiced monotheistic religion, somehow having come to believe in a single, loving God ("No Exit").
Fifty-two years before the Fall of the Twelve Colonies, the Centurions rose up against their masters and rebelled, waging a brutal war that lasted twelve years. The first Cylon War was staged both in space and on the surface of several Colonial planets, including Tauron and other outlying worlds. Centurions were present at these locations, fighting hand to hand against the Colonial Military and civilian fighters, as well as piloting raiders and commanding basestars in battle against the Colonial Fleet ("Razor").