Cyber-Wars

The Cyber-Wars was a galactic conflict in which a concerted effort by a united force set out to wipe out the Cybermen in 2526. The Cybermen tried to prevent this by destroying the Earth with a Cyber-Bomb and then by crashing a Human freighter into the Earth, however both these attempts were stopped by the Doctor. (DW: Earthshock)

It was during this time that the glittergun was developed as a weapon against them. It would fire gold dust at Cybermen, gold being a major weakness to them. The Wars resulted in remnant groups of Cybermen fleeing across the galaxy. One group tried to destroy Voga, a planet of gold. (DW: Revenge of the Cybermen)