[RayChuang88]

In fact, historically after the Roman Empire fell, Europe thrived surprisingly well because it was in many ways warmer up to the 1300's than now. But once the cold returned (plus the arrival of bubonic plague), Europe went into a steep decline that it didn't recover from until the 17th Century--and then Europe went into another very cold period when sunspot output dropped to zero--the famous Maunder Minimum between 1645 and 1715.

[Paul R.]

Yes, and those were minor drops in temperature, compared to the ones that almost killed off humans more than once.