nixtamalisation of corn, for example, a pretty darned sophisticated method of processing grains, should figure right up there with crop rotation and the wheel, but since it was invented in the "dawn of history" by "illiterate savages" it doesn't count. it always makes my skin crawl when I hear some average schmo who can't tell one plant from another call "illiterate" some person from, say, 1000 years back who could identify thousands of plant species on sight and know all their alimentary and medicinal properties. The difference between theory and practise in practise ...
http://en.wikipedia.org/wiki/Nixtamalization