Read here. (map from Mapquest.com). Many of the peer-reviewed research studies on historical climate conditions reveal an extended Medieval Warming Period that had two distinct high warmth peaks. The second peak around the 1400-1550 AD period was not as warm as the first peak (1000-1300 AD) but still produced climate temperatures similar to modern day temperatures. This second MW peak shows up well in the research on a sediment core from Venezuela's Cariaco Basin. (click on image to enlarge)
"Working with a sediment core extracted in 1990 from the northeastern slope of the Cariaco Basin, the authors derived an 800-year Mg/Ca history of the planktic foraminifer Globigerina bulloides....What stands out most boldly of all, however, is the remarkable rise and fall of the region's SST that occurred between the Medieval Warm Period and the Little Ice Age, which we call the Little MWP....Compared to its "bigger brother," the Little MWP gets much less respect. Nevertheless, its prowess is indicated by the fact that Black et al. write that "on average, twentieth-century temperatures are not the warmest in the entire record," which prize must obviously go to the central portion of the Little MWP."
More historical charts here. Other climate history postings here. Modern temperature charts.