Read here. (h/t Tom Nelson) Archeologists are finding human artifacts that were buried under snow and ice hundreds of years ago. The discoveries clearly indicate that temperatures in this region were significantly warmer 1,000 years ago, thus allowing humans to thrive before the Little Ice Age cold made that impossible.
This actual evidence refutes the infamous hockey-stick portrayal that only modern temperatures are "unprecedented."
Previous climate-history postings. Map source here.