Fall of Gallifrey

The Fall of Gallifrey was when the Eye of Time, possessed by the Time Lords, was lost. It eventually fell into the hands of the New Dalek Paradigm after the Last Great Time War. (VG: City of the Daleks)

The "Fall of Gallifrey" presumably referred to the Time War, where Gallifrey, along with the Time Lords and the Daleks, was destroyed by the Doctor using the Moment.