Battle of Cassius

The Battle of Cassius took place near the planet of Cassius beyond Pluto's orbit. It occurred after the First Doctor's defeat of the Daleks' plot to turn occupied Earth into a mobile warship, which resulted in the occupation force being crippled. (TV: The Dalek Invasion of Earth).

The decisive moment came when Commander David Jarvis, aboard the Colonial warship Dauntless, disregarded orders and fired a critical volley. (PROSE: The Crystal Bucephalus)

At the conclusion of the battle, the Daleks' solar system blockade was shattered, forcing them to leave Earth. (PROSE: Love and War)