Howling:The Silence's war against the Doctor

In A Good Man Goes to War, Madame Kovarian describes the conflict between the Doctor and the Silence as an "endless, bitter war." It's been suggested that this war could go all the way back to the Doctor's first incarnation, but due to the memory-defying abilities of the Silents, he doesn't remember it. What events that occured in the classic series could have been instigated by the Silence to get the Doctor out of the way? 82.2.136.93talk to me 23:19, April 1, 2012 (UTC)