A Gallifreyan Military Base was set up on the Moon of Tenacity in the Tenacity system. It was used to train Time Lords for combat in the Last Great Time War.
The War Ollistra brought the Eighth Doctor and his companions there, enlisting the Doctor in the military training and sent his companions off for questioning. (AUDIO: The Conscript)
After the Daleks invaded, it was destroyed alongside the rest of the Tenacity System when they used a reversal wave. (AUDIO: One Life)