Pandora

Pandora was the first female President of the Time Lords. Following her election, she revealed her true tyrannical nature and declared herself Imperiatrix.

Early career
According to legend, she sought to overthrow the traditions of Rassilon, lead Gallifrey to war and use time travel to reshape the Web of Time to her own design. She used an off-world bodyguard who killed all who opposed her will. In time, however, the High Council managed to convince the bodyguard to betray her mistress in return for the Time Lords improving her people's livelihood. (AUDIO: Lies)

Punishment by the Time Lords
However, once Pandora was betrayed, the High Council took the bodyguard back to her planet, where she was placed in an eternal 6.8 second time loop from which there was no escape.

The captured Pandora was dispersed in such a thorough manner in that she never existed in the first place. She existed only in legends. The dispersal chamber was in the old Capitol, which was destroyed in Gallifrey's civil war. The new Capitol was built over the ruins, which became the Vaults. The legends said that Pandora's dying screams still could be heard in the Vaults where she eternally cried out for vengeance. (AUDIO: Imperiatrix)

Return
From her last remaining presence in the Matrix, Pandora manipulated Time Lord genetics through the centuries until the result was Romana. During her time at the Time Lord Academy, Pandora's voice enticed Romana into visiting the Vaults. Pandora told Romana of her Imperiatrix Imprimatur, and of her destiny to rule Gallifrey under her influence. Disturbed by the encounter, Romana told her tutor, Irving Braxiatel. He used his skills to hypnotise her into forgetting both Pandora and himself.

Sometime later, during her travels with the Fourth Doctor, torture by the the Shadow, an agent of the Black Guardian released the hidden memories. After the conclusion of this adventure, Romana regenerated in order to repress them. Now in her second incarnation, Romana continued to travel with the Doctor for a time before exiling herself in E-Space.

Pandora apparently engineered Romana's return to Gallifrey and her ascension to the Presidency after the disastrous Lady President Flavia was deposed. Braxiatel had supported her campaign in order to closely observe her for any sign of continued influence by Pandora. (Romana was unaware she had ever known Braxiatel personally.)

During her Presidency, accompanied by her own off-world bodyguard, Leela, Romana again encountered Pandora, who used the energy of Coordinator Narvin to take the physical form of Romana's own first incarnation. Through this meeting, Romana learned of her own history. Pandora was trapped in the Matrix by K9, but only temporarily. (AUDIO: Lies)

Shortly afterwards, Castellan Wynter came into contact with Pandora and was driven mad. As a more stable solution, Braxiatel absorbed the past and present aspects of Pandora from the Matrix and went into exile to isolate her from other Time Lords (specifically the most ambitious of them - Darkel), leaving the future aspect still present. (AUDIO: Pandora) In spite of the risks involved, Romana continued to seek advice from Pandora through K9, on the various challenges facing her rule. Pandora's advice was generally to declare herself Imperiatrix and to rule by decree.

Darkel, meanwhile, had been receiving guidance from a disembodied voice in the Vaults and challenged Romana for the presidency. Before an election could be held, Romana declared herself Imperiatrix and dismissed the High Council. Pandora materialised (again in the form of the first Romana) claiming superior rights to the title. (AUDIO: Imperiatrix)

A short but bloody civil war ensued, ranging the more reactionary forces of Pandora (including Darkel, Valyes, Janartis and, superficially, K9) against the more progressive elements and those concerned with maintaining the technicalities of the succession (Romana, Leela, Narvin, Hallan, Annos and, waveringly, Matthias). The war was won not by military might, but rather by Romana and K9 tricking Pandora back into a Matrix partition, and then destroying the Matrix entirely, killing this aspect of Pandora. (AUDIO: Warfare)

The remaining aspects of Pandora became a force of pure hate, and when Braxiatel returned to Gallifrey and was cajoled into releasing the force by Darkel, it consumed Darkel rather than Braxiatel. With still a tiny part of Pandora remaining in his mind, Braxiatel then returned to his exile, the threat apparently neutralised. (AUDIO: Mindbomb)

Pandora was later removed from Braxiatel's mind by Avril Fenman and sent into the mind of the Braxiatel on the Braxiatel Collection. (AUDIO: The Curse of Fenman)

Behind the scenes
The story of Pandora's rise to power mirrors the story of Majestrix Pengallia in Apocrypha, which was referenced in The Infinity Doctors.