Cyber-invasion (The Wheel in Space)

In the 21st century, the late CyberFaction attempted to invade the planet Earth using Space Station W3. (TV: The Wheel in Space, AUDIO: The Early Cybermen)

Origin
In the late 20th century, the early CyberFaction waged an invasion of Earth which was defeated by the Second Doctor. (TV: The Invasion, AUDIO: The Early Cybermen) As noted by the Cyber-Planner which led the attack on Space Station W3, the Doctor was "known and recorded" as an enemy of the Cybermen. (TV: The Wheel in Space)

Invasion
Intending to use it as a beacon for their invasion fleet, the Cybermen attacked Space Station W3. The Second Doctor freed the crew from the Cybermen's hypnotic control and destroyed their fleet. (TV: The Wheel in Space, AUDIO: The Dying Light)

Aftermath
Following the Cybermen's defeat, crew member Zoe Heriot entered the TARDIS and joined the Doctor and Jamie McCrimmon as a travelling companion. (TV: The Wheel in Space)

After some time travelling with the Doctor and Jamie, Zoe Heriot was returned by the Time Lords to Space Station W3 at a moment in time before she went away in the TARDIS (thus erasing her memories of all bar her first adventure with them), where she was met by Tanya Lernov and for a moment had the feeling of having forgotten something important, which she quickly dismissed. (TV: The War Games)

The Cybermen later launched a second attack on the Wheel, but were sent into the Land of Fiction by Zoe Heriot. (AUDIO: Legend of the Cybermen)