The Daleks broke into two factions shortly after the creation of the Daleks and the destruction of the Kaled City. The Daleks realised that Davros was impure as he was not 100% Dalek, so they turned against him and exterminated him. (TV: Genesis of the Daleks) Many years later he was woken again. The seeds of war began less than a day after the forces of the Supreme Dalek woke Davros from suspended animation. (TV: Destiny of the Daleks)