Salyavin Salyavin was an infamous criminal Time Lord , who used his unique power of mind - control to make others do his will . Despite being a dangerous and wanted criminal , the Doctor grew up looking up to the man . After being caught by his own species , he was sentenced to be held on Shada , a prison planet . He escaped shortly into his sentencing and took on the false identity Professor Chronotis . When he moved to Earth from Gallifrey to retire , he took with him the " The Worshipful and Ancient Law of Gallifrey " , which was the key to finding the prison , so that no one could ever find it . Biography . As Salyavin . Salyavin lived over ten thousand years before the Doctor ' s time . ( PROSE : " Shada " ) Like all Time Lord s , Salyavin was taken from his family at the age of eight for the selection process in the Drylands . Staring into the Untempered Schism as part of a Time Lord initiation rite , Salyavin was driven mad by what he saw in the Schism . ( PROSE : " A Brief History of Time Lords " ) He had great mental powers , and was able to move his mind into another ' s . Though he had no malicious intent , the High Council was suspicious of him and his powers . Though he continued to move up the ranks , he simply wanted a quiet life of reading . The Council decided to trick him , sending him to Shada as an official and planning to trap him inside forever . Salyavin instead took control of his guardians , allowing him to escape . He then used his powers to make Salyavin into a myth and changed his identity to Chronotis . He also removed the knowledge of Shada from their minds , as well stealing the book " The Worshipful and Ancient Law of Gallifrey " . ( PROSE : " Shada " ) As Chronotis . Chronotis lived a quiet life , acting as a librarian for nearly 12 , 000 years . Eventually , for his years of service , the Time Lords allowed him to retire to another planet . He decided to move to St Cedd ' s College in Cambridge around the 17th century and lived in his TARDIS , disguised as his living quarters at the College . ( PROSE : " Shada " ) He had lived at the college for some time by 1889 . ( COMIC : " The Time Machination " ) Chronotis met the the Doctor in 1955 while he was in his fourth body and travelling with Sarah Jane Smith . A few years later , the First Doctor met Chronotis for the first time . ( PROSE : " Cambridge Previsited " ) The Doctor grew to know him as a friend , though he did not know of the connection between Salyavin and Chronotis . ( PROSE : " Shada " ) When Salyavin began approaching his thirteenth incarnation , and thus the end of his cycle of regeneration s , he sent a message to the Fourth Doctor to come and see him so he could return " The Worshipful and Ancient Law of Gallifrey " , which he had stolen . ( WC : " Shada " ) At the same time , Skagra was looking for a way into Shada and access to Salyavin . Combining a mind stealing sphere and Salyavin ' s ability to implant his mind , Skagra planned to merge minds with everyone in the universe . ( PROSE : " Shada " ) Salyavin died when Skagra ' s sphere attacked him , searching for information about " The Worshipful and Ancient Law of Gallifrey " . Skagra didn ' t realise that Chrontis was Salyavin . Due to a serendipitous mistake made by Clare Keightley with Salyavin ' s TARDIS , he was brought back into existence . ( WC : " Shada " ) Skagra eventually made it to Shada , where he found out that Salyavin wasn ' t there . Unfortunately , Chris Parsons worked out who Salyavin was while he was in the room , allowing Skagra to take over his mind . After the Doctor defeated Skagra , Salyavin returned to Cambridge to live as Professor Chronotis . ( PROSE : " Shada " ) References . In 1889 , the Tenth Doctor mentioned Professor Chronotis to Jonathan Smith , asking if Smith , a man supposedly from Cambridge , knew Chronotis . ( COMIC : " The Time Machination " )