Both the Time Lords and the Daleks issued a declaration of war against each other, formally beginning the Last Great Time War. (AUDIO: Celestial Intervention [+]Loading...["Celestial Intervention (audio story)"], PROSE: Father of the Daleks [+]Loading...["Father of the Daleks (short story)"])
According to one account, the Daleks declared war against the Time Lords after discovering that they had tried to tamper with history to prevent the creation of the Daleks. (PROSE: The Visual Dictionary [+]Loading...["The Visual Dictionary (2007 reference book)"]) According to another account, a Dalek Puppet Emperor openly declared his hostility to the Time Lords of Gallifrey during the time leading up to the war. (PROSE: Meet the Doctor)
Upon the official outbreak of the War, the Daleks contacted Davros on Alacracis IV, asking for his help in the conflict. Filled with pride at his children, he accepted. (PROSE: Father of the Daleks [+]Loading...["Father of the Daleks (short story)"])