Archibald Hamish Lethbridge - Stewart Archibald Hamish Lethbridge - Stewart was a member of the Lethbridge - Stewart family who served in the British Army in World War I . He served at Ypres in December 1914 and , following an encounter with the Twelfth Doctor and First Doctor , participated in the Christmas Armistice . ( TV : " Twice Upon a Time " ) He was the brother of Alistair Lethbridge - Stewart and the great - uncle and biological grandfather of Brigadier Alistair Gordon Lethbridge - Stewart . ( PROSE : " Night of the Intelligence " ) History . In 1902 , while her husband was off on a mission , Lillian Lethbridge - Stewart , in a moment of loneliness , turned to Archie , her brother - in - law , and a night of indiscretion followed . Nine months later she gave birth to her second child , Gordon . Everyone believed the father to be Alistair . ( PROSE : " The Note " ) He served at Ypres in December 1914 . On Christmas Day , Archibald was stuck in a crater with a wounded German soldier , where both men held each other at gunpoint . Archibald stated that he wouldn ' t kill the German soldier except in self - defence , but recognised that they couldn ' t understand each other . Before they could kill each other , Archibald was abducted by the Testimony in order to record his memories . Due to an error in the timeline caused by the First Doctor and the Twelfth Doctor resisting regeneration at the same time , Archibald was returned to Antarctica in December 1986 instead of Ypres , where he became the subject of a conflict between the two Doctors and the Testimony , who wished to return Archibald to his own time . After the truth about the Testimony was revealed , it was agreed that Archibald would be returned to his own time period , with the Doctors acting as his escort . On the return trip aboard the Twelfth Doctor ' s TARDIS , Archibald expressed regret that he would never see his wife and sons again to the Doctor . After returning to Ypres , Archibald was informed that his memory of the entire experience would be erased while a perception filter would keep him from seeing the two Doctors . The First Doctor expressed regret that " the universe generally fails to be a fairy tale " , and Archibald revealed his name and requested that the Doctors check up on his family . After both Doctors promised to fulfill his request , Archibald returned to his spot in the crater , causing time to resume and his memories to instantly be erased . As Archibald and his German opponent prepared to shoot each other , both men heard Christmas caroling on both sides , as a " Christmas truce " began . Laughing in relief , Archibald and the German soldier ended their standoff and Archibald called for medical attention for the man . Privately the Twelfth Doctor explained that he adjusted Archibald ' s timeline by a couple of hours to save Archibald and his opponent ' s lives . Some hours later , as the truce began to end , Archibald noticed the Twelfth Doctor standing on the field and saluting him , causing Archibald to confusedly salute back . ( TV : " Twice Upon a Time " ) Archibald visited his brother , Alistair Lethbridge - Stewart for Christmas in Carmunnock , 1917 . Archie ' s train was delayed , so he had to take an alternate train in London , arriving on 26 December instead . He had a drink with his brother to celebrate both their offspring ' s future . ( PROSE : " What ' s Past is Prologue " ) Original timeline . In an alternate timeline , Archibald and his German opponent killed each other on the battlefield . ( TV : " Twice Upon a Time " )