Galah was a Time Lord who lived a long, tedious life as a Gallifreyan sculptor and pacifist.
She went to the Time Lord Academy with the Doctor. They were never close, due to a difference of opinions regarding the nature of good and evil. Galah believed that goodness was a state of being rather than a process.
At one time, she materialised her TARDIS on an asteroid named Victoria and created a dreamscape based on Wychborn House by hooking herself up to the protyon unit inside her TARDIS' console. (PROSE: Strange England)