Frontier in time The frontier in time was the edge of the Great Houses ' noosphere in the universe ' s far future , past which they could not see or safely travel . The frontier appeared as the posterior end of recordable history in the Spiral Politic and obscured the homeworld s of many posthuman cultures . The concept of a destination being " too far in the future " was meaningless to the Houses ; their travel past the frontier was limited only because so many other time - aware cultures were active in the later universe . Since they preferred to believe themselves to be masters of causality and overseers of the whole continuum , members of the Houses rarely ventured into the frontier . ( PROSE : " The Book of the War " ) The Tenth Doctor said that Time Lords never went as far as the year 100 , 000 , 000 , 000 , 000 , though hid there during the Last Great Time War . ( TV : " Utopia " ) The Eighth Doctor needed to force his TARDIS to visit Endpoint in an attempt to see how far in the future he could go ; it needed to recalibrate before it could dematerialise again . ( PROSE : " Hope " ) Faction Paradox had no difficulty crossing the frontier and voyaging into the depths of the posthuman period , where they had links with underworld and even terrorist cabals ; though the Houses accused them of conspiring with posthumans who scavenged wrecked Homeworld technology , the Faction instead voyaged past the frontier just for the satisfaction of doing something the Houses had made taboo . During the War , the enemy patrolled the frontier and the areas beyond , suggesting that enemy forces may have been in full operation beyond the frontier . Homeworld timeship s were frequently repelled from this region of the Spiral Politic and , more disturbingly , as many as five were destroyed or captured along with their occupants . Compassion found the crumpled remains of the 103 - form timeship Percival on the frontier , abandoned on a barren rock on the edge of posthuman history . Percival ' s pilot was still alive despite having been stripped of all his major organs , though he died after a few hours on the Homeworld . Carmen Yeh told of this event and Compassion ' s subsequent confrontation of the War King in her fictionalised memorial " Fantastical Travels in an Infinite Universe " . The Uptime Gate to the City of the Saved was located in the universe almost exactly on the frontier in time . The Book of the War suggested that this might imply detente or even alliance between the City and the enemy forces patrolling the frontier . Zo la Domini was one of the markers of the frontier in time ; after a Violent Unknown Event occurred there , Thessalia chose another location on the frontier ( PROSE : " The Book of the War " ) to unleash the babel . ( PROSE : " Newtons Sleep " ) Simia KK98 was on the edge of the Great Houses ' noosphere . When an expeditionary cohort of the Seventh Wave was cut off from Homeworld contact close to the frontier with only an outmoded 89 - form timeship , Quintessence Officer Hierarchio predicted their chances of return to be minimal and suggested that they settle on one of the still - accessible worlds . There , the troops visited the Anvil Star s region and observed the birth of new universe s and the creation of Leviathan s . ( PROSE : " The Book of the War " )