Skirmish between the Halldons and the Eternals

A skirmish between the Halldons and the Eternals was, according to one account, one of the only two time wars fought by the Time Lords of Gallifrey prior to the Great Time War which ended in their destruction. Much as the name of the event implied, the conflict had mostly been between the Halldons and the Eternals, with the Time Lords only stepping in at the conclusion to put an end to the hostilities which had begun to threaten the universe. (PROSE: Meet the Doctor)