The Tormund quote about the White Walkers has always fascinated me. What has never been quite clear to me is whether he was talking just about the recent trek towards the Wall when he was describing the precautions they took against the Walkers, or whether the Walkers had always lingered around, and had never actually been truly driven into “extinction” or into the Heart of the North as the tales had said.

It seems to have been something that started relatively recently, because it hasn’t been often enough that any ranger has seen signs of it prior to poor Waymar Royce, and Royce was the first ranging to go missing, so it’s not like anyone noticed it and then was vanished. 

Tormund talks about it as something that the wildlings have been dealing with for a while now: 

Tormund turned back. “You know nothing. You killed a dead man, aye, I heard. Mance killed a hundred. A man can fight the dead, but when their masters come, when the white mists rise up … how do you fight a mist, crow? Shadows with teeth … air so cold it hurts to breathe, like a knife inside your chest … you do not know, you cannot know … can your sword cut cold?”

While Mance is a bit of a badass, I doubt a hundred refers to just one or two fights. This suggests that he’s been dealing with the wights for at least a few months prior to him holing up in the Frostfangs between AGOT and ACOK, because by the time Jon meets him, Mance has put counter-measures in place, which suggests some amount of learning about one’s enemy through observation and trial and error.