Katarina Katarina was a Trojan servant who became a companion to the First Doctor for a very short time . She worshipped the Doctor as the god Zeus and sacrificed herself to save his life . Because of the relatively short time that she travelled with the Doctor , Katarina ' s contact with other companions was very limited . She was most acquainted with Steven Taylor , who was with the Doctor before and she also met Vicki Pallister briefly . Biography . The Seventh Doctor first met Katarina when she was a little girl living near Troy . She spoke to him of her ambition to serve as handmaid to a priestess because her poor family could not afford to feed her any longer . The Doctor gave them a gold coin to alleviate their poverty but , on learning Katarina ' s name , he realised that she would die young ( as he had already witnessed it in his personal timeline ) . ( PROSE : " An Unfulfilled Dream " , TV : " The Daleks ' Master Plan " ) As a young woman , Katarina served Cassandra , princess of Troy . She was little more than a slave . In circa 1200 BC , Cassandra sent her to spy on the First Doctor and his friends , particularly Vicki Pallister , known to her as Cressida , to gather evidence she was a Greek spy . To this end , Katarina befriended Vicki , who sent her to help the Doctor get Steven Taylor back to the TARDIS after a spear thrust had badly injured him . Katarina tended to Steven ' s wounds . She joined Steven and the Doctor on their travels . ( TV : " The Myth Makers " ) Katarina came from a simple time and never truly understood where she was or what was happening to her . She mistook the TARDIS for the Place of Perfection and the Doctor for the god Zeus , come to take her on a journey in his temple to the real Place of Perfection . Despite the Doctor ' s protestations to the contrary , she remained set in this belief . When the criminal Kirksen held Katarina hostage in an airlock to blackmail the Doctor into returning Mavic Chen ' s ship , the " Spar " , to the planet Kembel and the Dalek s , she deliberately activated the airlock door and expelled herself and Kirksen into space , causing their deaths in the vacuum . She was certain her death had been foretold and that she was doomed to die . ( TV : " The Daleks ' Master Plan " ) Aftermath . After the Doctor defeated the Daleks , Steven Taylor said that he had seen too much death lately ; the sacrifice of Katarina weighed on his mind , among others . ( TV : " The Daleks ' Master Plan " , " The Massacre of St Bartholomew ' s Eve " ) In the afterlife , Katarina found herself without a coin and unable to cross the River Styx . Due to the intervention of the First Doctor ( or her idea of him ) , she found her way not only to Asphodel , where all souls who had done neither good nor evil would go , but to the Elysian Fields , the abode of the blessed . ( PROSE : " Katarina in the Underworld " ) Much later , on the ruined world of Adeki , the Seventh Doctor found one of several Gwanzulum s , beings who used their shapeshifting powers to pass themselves off as some of the Doctor ' s past companions , including Katarina . Before he realised the ruse , the false Katarina tried to have him take her off the planet . ( COMIC : " Planet of the Dead " ) Later , inside the inner landscape of the Doctor ' s mind in a hell haunted by his guilt , Ace came across the ghost of Katarina in the form of an eternally frozen girl of ice . ( PROSE : " " ) While in the Divergent Universe , the Eighth Doctor was shown an illusion of Katarina by the Kro ' ka . He stated that he regretted taking Katarina from her own time and giving her hope , only for her to be killed shortly afterwards . ( AUDIO : " The Last " ) Undated events . At some point , Katarina was taken to the Black Archive by UNIT to have her record as a companion of the Doctor taken . Her memories of the visit were subsequently erased and she was sent on her way . ( TV : " The Day of the Doctor " ) Behind the scenes . " Doctor Who " producer John Wiles and his production team decided to write out Katarina as soon as possible to get around the writing challenges of a character so very unused to modern concepts , and to whom the Doctor would have had to explain everything — for example , Katarina did not even know what a key was . They decided to do so in the most dramatic way possible .