Attack on Voga
From Tardis Wiki, the free Doctor Who reference
As recalled by the Fourth Doctor, the Cybermen waged a failed attack on Voga, either "at "the end" of the Cyber-War (TV: Revenge of the Cybermen) or "after the end" of the Cyber-War. (PROSE: The Revenge of the Cybermen) Most of their ships vanishing after the attack, (PROSE: The Revenge of the Cybermen) the Cybermen disappeared with humanity believing them to have died out. Centuries later, the CyberNomads made a second attempt to destroy Voga, but were defeat by the Doctor. (TV: Revenge of the Cybermen)
