Siege of Trenzalore The Siege of Trenzalore was a conflict which lasted 900 years , ( PROSE : " " ) initiated by a message broadcast through time and space that no one could understand . History . Foreshadowing . Towards the end of his farewell tour , the Eleventh Doctor wished to know the Silence ' s motive for engineering what appeared to be his fixed death at Lake Silencio . His search led him to Dorium Maldovar , whose severed , still living head he found at the Order of the Headless ' Seventh Transept . Explaining to the Doctor that the Silence wished to avert his " dangerous " future , Dorium elaborated by telling him the prophecy , " " On the fields of Trenzalore , at the fall of the Eleventh , when no living creature can speak falsely , or fail to answer , a question will be asked . A question that must never , ever be answered . " " Revisiting Dorium after escaping his death , the Doctor was reminded by Dorium that the future told in the prophecy was still waiting for him . ( TV : " The Wedding of River Song " ) The beginning . The Papal Mainframe arrived at Trenzalore first and , recognising the significance of the message , created a force field around the planet to protect the small village there . Unknown to them , the Weeping Angel s had already arrived and hid in the snow planetside . By the time the Eleventh Doctor arrived , hundreds of starship s had gathered , including those of the Dalek s , Cybermen , Sontaran s , Slitheen , Judoon , Terileptil s , Silurian s , Ice Warrior s , Auton s , Krynoid s , and the Mara . Mother Superious , Tasha Lem , assisted the Doctor and Clara Oswald in reaching the planet . When the broadcast was revealed to be the First Question , sent from Gallifrey , trapped in a pocket universe and emanating through a crack in time and space , the Doctor refused to leave the planet to be destroyed by his enemies in space , all of whom would seek the destruction of the Time Lord s . However , he also wouldn ' t bring the Time Lords back through the crack , fearing the Last Great Time War would start anew . Tasha Lem , changing the faith of the Papal Mainframe into the Church of Silence ( to prevent the Doctor saying his name , bringing the Time Lords back and restarting the Time War ) , initiated the Siege of Trenzalore . ( TV : " The Time of the Doctor " ) The conflict . Over the next three centuries each of the Doctor ' s enemies tried various means of penetrating the force field created by the Church of Silence , each time defeated by the Doctor ' s ingenuity . It was during this time that the Kovarian Chapter led by Madame Kovarian broke away from the Church , travelled back along the Eleventh Doctor ' s time stream and attempted to kill the Doctor so he would never reach Trenzalore . Their first attempt involved them blowing up the TARDIS which the Doctor prevented . However , in doing this , Kovarian and her faction ended up creating the cracks in time in the first place , effectively causing what they sought to prevent . The Doctor called this the Destiny Trap : " You can ' t change history if you ' re part of it . " The fleet s above Trenzalore made various attempts to sneak past the force field - such as the Sontarans using an invisibility cloak or the Cybermen using a low - tech wooden unit . ( TV : " The Time of the Doctor " ) This also incuded the Ice Warrior s burying Christmas through an avalanche , ( PROSE : " Let it Snow " ) a blind Tsunami Snake , ( PROSE : " The Dreaming " ) a Krynoid . ( PROSE : " An Apple a Day . . . " ) and the Nestene Consciousness parachuted in the Auton s . ( PROSE : " Strangers in the Outland " ) The Daleks , however , turned their attention to the Church itself . After calling for reinforcements , they assaulted the Mainframe , turned everyone into Dalek puppet s and penetrated the field afterwards , followed by the Cybermen and the other fleets . ( TV : " The Time of the Doctor ) " 750 years into the Siege the Mara entered Christmas and possessed the town ' s children , trying to force the Doctor to say his name and begin a new Time War , but the Doctor defeated them . ( PROSE : " The Dreaming " ) Allying himself with the Papal Mainframe ' s soldiers and Confessional Priests ( now known as the Silent s ) , the Doctor repelled each attack , and eventually all attackers had either been destroyed or had retreated save for the Daleks who continued to attack the village in Dalek fighter pod s and a massive Dalek saucer . Finally , dying of old age after nine hundred years of fighting , the Doctor was ready to admit defeat to his oldest enemies . However , when the Time Lords used the crack to grant him a new regeneration cycle , having been persuaded to do so by Clara Oswald , the Doctor was quick to defy the Daleks , and used the excess energy from his thirteenth regeneration to destroy their forces , effectively ending the siege ( TV : " The Time of the Doctor " ) and changing the future he had previously been made aware of . ( TV : " The Name of the Doctor " ) Aftermath . With the Daleks defeated , the people of Christmas saved and the crack finally closed by the Time Lords , the Doctor retreated to his TARDIS . Despite being restored to a youthful appearance during his regenerative " reset " on the clock tower , he was still dying of severe old age . Before regenerating , he used the TARDIS telephone to send a parting message to Clara in the near future relative to his regeneration , as a way of easing the stressful experience of adjusting to his new incarnation , then reunited with the present - day Clara . ( TV : " The Time of the Doctor " , " Deep Breath " ) Freed from his obligations to both the Time Lords and the people of Christmas , the Doctor set the TARDIS in flight and made good his departure from Trenzalore . After saying an emotional farewell to his companion , he finally succumbed to his advanced age and regenerated into the Twelfth Doctor . ( TV : " The Time of the Doctor " ) As recorded by the Testimony , the Doctor ' s participation in the siege earned him the epithet " Beast of Trenzalore . " ( TV : " Twice Upon a Time " ) Original timeline . In an alternate timeline , the Time Lords never gave the Doctor a new regeneration cycle , and the Siege of Trenzalore ended in a victory for the Doctor ' s enemies with the Doctor himself dying . Trenzalore became a desolate , volcanic wasteland with its moons and rings destroyed and a battlefield graveyard covering the planet ' s surface for the millions who had died during the battle . The biggest of these graves was the Doctor ' s in the form of his dying TARDIS , which was suffering from what the Doctor called a " size leak " . ( TV : " The Name of the Doctor " ) Notes . According to the Great Intelligence , while the Siege was a massive battle that millions died in to everyone else , to the Doctor it was a " minor skirmish " compared to the other bloody battles he had fought in , particularly in the Last Great Time War . ( TV : " The Name of the Doctor " )