Claire Bartlett

 was a Diensberg, Massachusetts resident and schoolteacher during the American Civil War who had an active correspondence with Union Captain Will Johnson.

In these letters, Johnson would share his most intimate thoughts about the progress and morality of the war, and she would reciprocate. He also gave specific detail about his encounters with the TARDIS, the Fifth Doctor — whom he knew only as a physician named John Smith — Erimem, Peri and even Abraham Lincoln. Bartlett was thus privy to information about many momentous occasions, such as when the Doctor saved Lincoln from assassination in Richmond, Virginia, when Lincoln entered Jefferson Davis' house for the first time, and even details about Lincoln's eventual slaying.

She was also friends with Paul LeVal, a Confederate officer whose fate Johnson followed partially on her behalf, since they were all mutual friends. Her brother George died before he reached his 23rd birthday, and Johnson provided her with information about this, as well. "I do not think I can even begin to imagine how you must feel, having fought so long in the war and met the President so soon before his death. But you must try to take solace from the knowledge that President Lincoln led us to a victory which now gives us the opportunity to rebuild out country and our families."

Due to the vagaries of the United States Postal Service during the war, Bartlett didn't receive any of Johnson's letters until after the war concluded. She then read all his mail en masse, sailing through years of conversation at once.

Thus she only ever wrote him two letters while he was away from home: one on 16 April 1861, when he was about to graduate from West Point, and another 5 May 1865, in the aftermath of Lincoln's death.

On this latter occasion, she accepted Johnson's marriage proposal, which he had only offered in his last letter, written after Federal victory was a reality.

Both she and her newly affianced remained committed to helping their friend LeVal overcome post-war trauma, even though Level had fought on the Confederate side. In this effort, Claire trusted Will's judgment that the Fifth Doctor could be of some great assistance. (PROSE: Blood and Hope)

Behind the scenes
This character's name is an obvious tip of the hat to the real word Claire Bartlett, Iain McLaughlin's long-time writing collaborator.