Gallifrey's time lock

Gallifrey's history was protected from potential Dalek incursions by a time lock during the Last Great Time War. (AUDIO: Legion of the Lost ^[+]Loading...["Legion of the Lost (audio story)"]) Nevertheless, the Daleks tried to travel back to prehistoric Gallifrey to prevent the Time Lords from evolving, (PROSE: Engines of War ^[+]Loading...["Engines of War (novel)"]) and the War Doctor himself travelled back to the First Segment of the war to thwart a Dalek plot. (PROSE: The Stranger ^[+]Loading...["The Stranger (short story)"]) however, the Twelfth Doctor unknowingly arrived on Gallifrey in his past in his TARDIS, which led Clara Oswald into meeting the First Doctor when he was still a child. (TV: Listen ^[+]Loading...["Listen (TV story)"])

Following the removal of Gallifrey from the universe, it was no longer time-locked and could be reached by TARDIS at its new position at the end of the universe following its release from the pocket universe. (TV: Hell Bent ^[+]Loading...["Hell Bent (TV story)"])