Spiridon army

The Spiridon army was a Dalek army, initially numbering 10,000, which was stored on the planet Spiridon in the Spiridon campaign. (TV: Planet of the Daleks)

The Dalek army on Spiridon was never recovered for the duration of the Second Dalek War, and in fact remained trapped in the ice for decades. (PROSE: The Whoniverse) Scholars of the incident devised different theories as to what ultimately happened to the army. In line with one theory popularised by Dalek historian Caul Pornell, (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) the Sixth Doctor directed Davros to Spiridon as part of a long game. Davros began converting much of the army into the first ranks of the Imperial Dalek faction, increasing their numbers from 10,000 to 4,000,000 in the process. The army allowed Davros to take the fight to the Dalek Prime, resulting in the hostilities of the Imperial-Renegade Dalek Civil War. (COMIC: Emperor of the Daleks!) A second account held that, during the Second Great Dalek Occupation, the Daleks of the Seriphia Galaxy attempted to pick up where their predecessors left off by creating an invisible army, but the Seventh Doctor infected them with light wave sickness and destroyed them. (AUDIO: Return of the Daleks) No matter the case, eventually, the only Dalek army left in hibernation was in the Fifth Galaxy. (WC: The Sentinel of the Fifth Galaxy)

Confronting after learning that he had survived his execution by the Dalek Prelature, the Dalek Litigator accused him of betraying "the Draconian Gambit, the army on Spiridon". The Master retorted that he chose to abandon those strategies as they "weren't working". (AUDIO: Vengeance)

During the Last Great Time War, the Time Lords believed that the Spiridon army was still frozen. Recognising the threat of the Daleks excavating this army for use against Gallifrey, it was recommended that reconnaissance TARDISes make regular sweeps of the Spiridon system, and that any increase in Dalek activity on the planet be reported to the War Council immediately so that appropriate action could be taken. (PROSE: Dalek Combat Training Manual)