Slide 5 in this series.
Cases of more extreme temperatures both hot and cold are well documented even in artwork. This era was followed by a warming period.
NEXT: There have also been legal challenges to the AGW organizations in the form of lawsuites.
This section on data fraud offers mulitple cases and angles on the general topic. It is however not exhaustive.
USHCN Monthly Temp Adjustments
The list can expand each week given the claims of AGW and their intent.