Last Battle of the Seventh Galaxy

The Last Battle of the Seventh Galaxy was the name given by historians to an event during the Time War. The Tenth Doctor described it as an unprovoked and avoidable massacre. "Touch a button and no more enemy. It didn't just destroy the enemy, no matter how many galaxies they were spread across; it also destroyed everything that had ever been known about that enemy."

- the Tenth Doctor's description of the weapon

As a result of the weapon used during the battle, countless star systems were annihilated. Two hundred million people perished on Arcopolis alone, but they weren't even noticed by the historians because they made up such a small fraction of the overall casualty figure. (PROSE: The Eyeless)