Genesis of the Cybermen

The creation of the Cybermen in the Doctor's universe occurred on the planet Mondas sometime prior to the 20th century, probably in the distant past.

Cybermen of the Doctor's universe
One account states that the planet Marinus was in fact an earlier name for Mondas. According to this account, the Voord acquired Worldshaper technology, which could accelerate time and turn themselves into full cyborgs. The Cyberman would later remember this planet as Planet 14. (DWM: The World Shapers)

Another account did not actually explain the earliest origins of the Cybermen, but showed how Cybermen existed on Mondas alongside the Lizard Kings, the Mondasian versions of Silurians, as well as the Sea Devils. These Cybermen died out until centuries later when Mondasian archaeologists discovered the remnants of ancient Cybertechnology. Presumably, the Mondasians would now go on to recreate the ancient Cybermen. (DWM: The Cybermen)

Yet another account shows that as Mondas travelled beyond the outermost planets of the solar system, conditions on the planet continued to deteriorate. The Doctor and Nyssa arrived on Mondas prior to the rise of the Cybermen. On Mondas, they discovered the inhabitants living in an underground culture similar to that of England in the 1950s, although with more advanced technology. They witnessed the Mondasians slowly slide towards cyber-conversion, as the CyberFaction had. The Mondasian cyber-conversion program was conceived by the cybernetic gestalt intelligence controlling Mondas as a solution to the planet's increasingly desperate situation. (BFA: Spare Parts)

The Cybermen would continue to evolve and change on Mondas. The CyberFaction, a group dedicated to more radical cyber-conversion, moved to Planet 14. The CyberMondasians stayed on their home planet. (NA: Iceberg, REF:Doctor Who: Cybermen))


 * This obviously contradicts the explanation for "Planet 14" given previously.

Other universes
Independently, John Lumic, the CEO of Cybus Industries created the Cybermen of a parallel Earth. (DW: Rise of the Cybermen/The Age of Steel)


 * See Cybus Industries and John Lumic

Continuity contraditions
Taken at face value, the origins of the Cybermen given in the Doctor Who Magazine comics feature The Cybermen conflicts with that given in Spare Parts and both do not accord very well with The World Shapers, which had earlier appeared in Doctor Who Magazine. Lance Parkin has speculated that perhaps Cybermen have originated in different planets and times independently, just as they had in different universes, as illustrated by the parallel universe Cybermen having no connection with the Cybermen of the main universe.

Alternatively, the Cybermen shown in The World Shapers may have preceded the ones in The Cybermen, though they do not match visually. (The former resemble the sleeker later Cybermen while the Cybermen of The Cybermen resemble the ones of The Tenth Planet.) The explanation of the creation of Mondas by the Constructors of Destiny in The Quantum Archangel also contradicts that given in The World Shapers.

"Genesis of the Cybermen" storyline
Gerry Davis, who had co-created the Cybermen with Kit Pedler, had written "Genesis of the Cybermen", an outline for a Cybermen origin story which David Banks included in his Doctor Who: Cybermen.