Martian invasion (The Seeds of Death)

An invasion of Earth was attempted by the Ice Warriors in the 21st century. (TV: The Seeds of Death)

Aftermath and legacy
According to Harold, who had watched a documentary about the Ice Warriors on the History Channel, the Ice Warriors were "supposed to have been wiped out" following the T-Mat incident. In the 23rd century, the Ice Warrior expert, Professor Schooner, declared the Ice Warriors "extinct" for "centuries", while Gregson Grenville had learnt in school that "[t]hey were all melted when the invasion fleet spiralled into the Sun". According to Grenville, nobody knew of any Ice Warriors existing after this period until the attack on Deimos Moonbase in the 23rd century.

Human tourists to the catacombs of Deimos in the 23rd century, such as Margaret, considered the moon the "final resting place" of the Ice Warriors and she and Harold expressed shock that "real" Ice Warriors could ever exist. One of the Ice Warriors that awoke from the tombs on Deimos considered him and eight others the last of their race. The Eighth Doctor corrected him, mentioning the tombs in the asteroid belt containing Ice Warriors yet to have been awakened. (AUDIO: Deimos)