18.104.22.168. Late Holocene Neoglacial Fluctuations
Records for the last 4,500 years generally indicate that temperatures were lower than the Holocene thermal maximum. A general cooling, known as the Iron Age neoglaciation, occurred between 2,500 and 4,500 years ago. A moderate climate amelioration followed near the dawn of the Roman Empire, before a return to cooler climates during the second half of the first millennia A.D. (the Dark Ages). Thence followed the Medieval optimum (1100 to 1300 A.D.), in which European temperatures reached some of the warmest levels for the last 4,000 years.