Salyavin - origins

Salyavin was one of the ancient Time Lords. His profound mental abilities enabled him to move his mind into the consciousness of other sentient beings.
He was himself entirely without malice and aspired only to being a quietly respected academic, but his tendency towards impish behaviour and childlike pranks, (often at the expense of high ranking Time Lords), resulted in him falling out of favour.
The High Council, paranoid at best and fearful that he might use his abilities to overthrow the Gallifreyan hierarchy, hatched a plot to trick him into visiting the prison planet Shada where they intended to trap him for all eternity, branding him a 'renegade' Time Lord.
Salyavin, however, was not so easily duped and planting into the minds of his guards the notion that they had already incarcerated him he sent them back to Gallifrey.
He then linked his own mind into his TARDIS's telepathic circuits, broadcasting his consciousness across Gallifrey and erasing all memory of Shada from the minds of the Time Lords, relegating its existence to myth and legend.
In this way he hoped to ensure that no-one would return to Shada and discover that his cell was empty.

The shear physical stress of this enormous feat, however, nearly killed Salyavin and he was forced to regenerate into a new body.

Professor Chronotis - eccentric academic

Taking advantage of his new incarnation he returned to Gallifrey under the name Professor Chronotis, a humble archivist, where he took up the post of 'Curator of the Panopticon Library'. His position gave him access to the tome, 'The Worshipful and Ancient Law of Gallifrey', (one of the artifacts of Rassilon and, significantly, the Key to Shada), which he stole, ensuring that his ruse would continue to go undetected.

He then relocated to 17th Century Terra (Sol III), obtaining an academic position in St Cedds College in Cambridge, where he sought to live his life in quiet obscurity.

While on Terra, he befriended The Doctor who, unaware that his strangely beguiling friend was also a Time Lord, (let alone the legendary and enigmatic Salyavin), and believing him to be a harmless if slightly eccentric academic, regarded him in the nature of a favourite uncle and paid him sporadic social visits.
Becoming increasingly forgetful during the latter years of his regeneration, however, and having mislaid 'The Worshipful and Ancient Law of Gallifrey' that he now wanted to return to the Panopticon Library, Professor Chronotis enlisted the help of The Doctor, and revealed his true identity to him.

Adventure ensued...
Reference Recordings: IV:35 - Shada

On hearing that Chronotis was reaching the end of his final regeneration The Doctor returned to St Cedds to visit his old friend one last time.
Delighted to meet with the Doctor again, in his final moments Chronotis reached into the mind of his compatriot and borrowed an imprint of the Doctor's own biodata, assimilating it into himself, cloning his likeness, and allowing him to procure further regenerations.
The Doctor, pleased to see his old friend fully rejuvenated, approved immensely of his choice of physical regeneration; "warm and sensible, something with a bit of style and... well style!"
In a final act, before parting from his friend, Professor Chronotis erased the memory of his regeneration from the mind of The Doctor, ensuring that his secret would be kept secure.

The Curator - reclusive archivist

Using his powers of persuasion Professor Chronotis secured for himself the post of 'Curator of the Under Gallery'; recording, cataloguing, and occasionally obtaining, items for Torchwood's secret archive below the National Portrait Gallery. He was thus finally able to achieve his ideal of being an academic archivist.

As 'The Curator of the Under Gallery', Professor Chronotis met with The Doctor, (now in his 12th incarnation), on just one more occasion, to reveal to him the true title of the painting 'Gallifrey Falls No More' that had been held in the Torchwood vaults.
The Doctor, sencing an overwhelming familiarity in the character and features of The Curator tried to quiz him further, but Chronotis, as was his nature, proved to be far more impish and enigmatic than he was informative.

Who Knows?... Who Knows?