Dalek-Movellan War

The Dalek-Movellan War, also called the Movellan War or Wars, was a galactic war fought between the Cyborg Daleks and the android Movellans. The Dalek Empire and the Movellans were each expanding to control the galaxy when they met and fought to destroy each other. According to the human historian Njeri Ngugi, it was "the most disastrous military campaign the Daleks fought."(PROSE: Remembrance of the Daleks)

Dating
Different dates have arisen concerning the war, which lasted for centuries.

The Twelfth Doctor described the conflict as "the past" to 21st century native Bill Potts. (TV: The Pilot)

In 4000, Gordon Lowery recalled the Movellan Wars as one of the last instances of Dalek activity in the galaxy, a thousand or more years before then. (PROSE: Mission to the Unknown)

The Movellan War was included in Vol XIX of Ngugi's The Children of Davros, a Short History of the Dalek Race, published in 4065. (PROSE: Remembrance of the Daleks)

The Matrix on Gallifrey recorded that Dalek and Movellan fleets were engaged in star system 4-X-Alpha-4 in 4949. (AUDIO: Neverland)

It is possible that some dates could be related to the later campaign fought by the Daleks, known as the Pa Jass-Gutrik, the "war of vengeance" against the Movellans. (PROSE: Remembrance of the Daleks)

The war
After visiting a distant planet in the future, the Twelfth Doctor arrived at some point during the war, and piloted the TARDIS to a war zone during a skirmish. He did this in order to sterilise the being that was following him, Nardole, and Bill. Nardole succeeded in sealing the area the Daleks were in. (TV: The Pilot)

For centuries, the two were locked in a long stalemate, each side's purely logical battle computers keeping them in deadlock. Hundreds of Dalek and Movellan battlecruisers flew across space, without a single shot being fired. To resolve this, the Daleks returned to their homeworld of Skaro to search the ruins of the Kaled dome for their creator, Davros. They believed that his unpredictable biological mind would allow them to re-program their computers to make unanticipated manoeuvres against the Movellans. The Movellans followed the Daleks to Skaro and ultimately learned of their plan. The Fourth Doctor, landing by chance on Skaro, was captured by the Movellans for the same reason. He later defeated both the Movellans and the Daleks, as well as the resurrected Davros. Davros was taken by Tyssan, a rescued Dalek slave worker, to Earth for trial. (TV: Destiny of the Daleks)

The Movellans defeated the Daleks in a battle of Traxana's sector of space. (AUDIO: Alien Heart)

After the trial, Davros was placed in a cryogenic freezer in a space station which served as his prison. The war continued for the next ninety or so years, until the Movellans developed a virus that could permeate the casing of Daleks and destroy them. (TV: Resurrection of the Daleks) According to Volume XIX of Ngugi's history, the Daleks, who had used biological weapons before, such as on Spiridon, failed to consider their own vulnerability to such an attack. The Movellan virus was so effective, therefore, because it took them completely by surprise. Overall, the Daleks suffered a casualty rate of 83% and much of the Empire in Mutter's Spiral collapsed. Various sector commands began trying to reorganise in the remaining isolated sectors, leading to increased factionalism that would plague Dalek politics into the 41st century. (PROSE: Remembrance of the Daleks)

Aftermath
The Dalek casualties necessitated the recruitment of Dalek troopers to fight for the Empire. The Supreme Dalek ordered Davros recovered from his prison so he could find a cure for the Movellan virus. During this time, the Daleks began using a different form of time travel — time corridors — although attempts to use the technology to prevent the losses of the war proved unsuccessful. (PROSE: Remembrance of the Daleks) They also used these to place duplicates to manipulate events for the Daleks' best interests. Following his revival, filled with more hatred than ever, Davros turned the Daleks on the Prison Station against each other, (TV: Resurrection of the Daleks) accentuating the factionalism which had resulted from the Movellan War. (PROSE: Remembrance of the Daleks) Wide-scale hostilities between the factions sparked the Imperial-Renegade Dalek Civil War. (TV: Resurrection of the Daleks, Revelation of the Daleks, Remembrance of the Daleks)

In later years, the Daleks launched the campaign Pa Jass-Gutrik, the "war of vengeance" against the Movellans, in which the Special Weapons Dalek participated. (PROSE: Remembrance of the Daleks)

Possible non-existence
The Dalek Prime claimed it had contrived a hoax of a war with the Movellans (whom the Daleks had created for the specific purpose of having an "enemy") as well as the Imperial-Renegade civil war as part of a plan to save Skaro from the Hand of Omega. (PROSE: War of the Daleks)