This cold spell would have preceded the Medieval Warm Period centered around 1000 AD that was followed by the already known Little Ice Age centered around 1600 AD. Note that no fossil fuel regulations or carbon taxes were used in creating this cold period. Note also this description of the consequences of that cold period:
The poor climate may been one of many factors contributing to societal changes of the era, including widespread crop failures and famines in Central Asia that may have triggered migrations from the area to China and Eastern Europe, thus helping spread an episode of plague (depicted in this 15th century painting) that originated there.
Famine and plague, caused by extreme cold, illustrating starkly that cooling is a far greater threat to human survival than climate warming. Meanwhile, the Medieval Warm Period saw a flourishing of American Indian culture in the American southwest.
So why do our modern climate doom-sayers fear warming so much, when there is no data to justify that fear, and plenty of data to suggest otherwise.