Sontaran Empire

The Sontaran Empire in Mutter's Spiral was the empire of the Sontarans which fought the Rutan Host in a long war which lasted millenia (DW: The Time Warrior)

In the 13th century, the Sontaran Commander Linx of the Fifth Sontaran Battle Group claimed Earth and its satellites and moons in the name of the Empire (DW: The Time Warrior)

One of the priorities given to Sontaran soldiers is the capture of a TARDIS. (EDA: The Eight Doctors)