Read here. Map source. Scientists analyze lake sediment core stretching back some 1,500 years. The core reveals extreme warmth of Medieval Warming and the cold of the Little Ice Age.
"The authors inferred the thermal conditions of Smreczynski Staw Lake in the Tatra Mountains of southern Poland via analyses of the distributions of various cladocera, chironomid and diatom species they identified and quantified in a sediment core they had extracted from the center of the lake in the spring of 2003, which contained sediments that had accumulated there over the prior 1500 years...once again we have another demonstration of the fact that the peak warmth of the late 20th-century and the early 21st-century has not been as unprecedented as the world's climate alarmists have typically claimed it to be."
Additional climate history postings.