Lord President (The Mark of the Rani)

During the First Rani's life on Gallifrey, mutated mice which she had created attacked a Lord President and his cat. The cat was eaten and the President got "a chunk" taken out of him. The President punished the Rani for this, (TV: The Mark of the Rani) with other sources confirming it as the reason she left Gallifrey. (PROSE: The Legacy of Gallifrey, Divided Loyalties)

remembered this incident, possibly suggesting it occurred prior to the Master's renegading and flight from Gallifrey; (TV: The Mark of the Rani) indeed, one account indicated that this occurred in the heyday of the Deca, when the President was Drall. (PROSE: Divided Loyalties)

However, in another account, the Scrolls of Gallifrey recorded the event as having occurred to the penultimate incarnation of Pandad IV, some time after the First Omega Crisis, with the injuries caused by the mice leading to him regenerating into his final incarnation — thus placing the Rani's exile from Gallifrey as far postdating the Doctor's and the Master's. (PROSE: The Legacy of Gallifrey) Indeed, another account claimed that by the time of the Doomsday Weapon crisis, the Doctor and the Master were the only two Renegades in stolen TARDISes yet active in the universe. (PROSE: Doctor Who and the Doomsday Weapon)