Rutan Empire

The Rutan Empire was the hive minded empire of the Rutan Host, ruled by the Rutan Queen.

History
Based on their homeworld, Ruta III, the Rutan Empire controlled the whole of the Mutter's Spiral once, before being driven to the fringes of the galaxy by the Sontaran Empire.

In the early 1900s, the Rutan Army made a series of strategic withdrawals to specific strongholds, viewed by the Doctor as them losing the war. The Rutan Battlefleet at this time sent a scout to Earth which was viewed by the Rutans as a strong point in the war. (DW: Horror of Fang Rock)

As of 2009, the Empire's war with the Sontarans had lasted 50,000 years, though this estimate was open to conjecture as other accounts stated the war has lasted millions of years. (DW: The Poison Sky)