I know that few armies manage to resist the temptation to rob the enemy population (and, very often, everyone else as well); but in England, when we think of pillaging, we usually think of Vikings .
The fact that the last instance of Viking pillage in Great Britain was about a thousand years ago has made no difference at all.
It must be the association with the Vikings, whom the English
imagine as particularly hairy and inclined to wear silly helmets (yes, the horns-on-the-helmets might not have been true, but the myth is, as so often, more powerful than the facts) that has given the word pillage a tinge of comedy and almost of affection.
This is why we can pillage a biscuit tin, or a stationery cupboard, or even Wikipedia.
I would still recommend avoiding anyone you see with horns on his helmet, though.
Thing To Do Today But Only In A Good Way: pillage. This word comes from the Old French pillage from piller, to despoil. Before that it may come from the Late Latin piliō, which probably comes from pilus, hair (see Vikings) or from the Old French peille, which means rag, from the Latin pīleus, which means felt cap (don't see Vikings).