What Caused the Little Ice Age?
					q The Little Ice age cooling was simply the culmination of a slow orbital-scale cooling.       If this is true, the medieval optimum warm interval may have been just an insignificant blip during an ongoing cooling trend. q The Little Ice Age was the most recent in a series of distinct millennial oscillations.       If this is true, the medieval optimum and preceding centuries may represent the warm extreme of a millennial oscillation, with a shift toward the cool extreme during the Little Ice Age.