Term (also Medieval Climate Optimum or Medieval Climate Anomaly) for a long period of time from about 900 to 1350 AD with a warm climate. The climate phenomenon occurred with different regional and temporal weightings. For in other places on earth it was much colder than today, for example in the tropical Pacific. The temperatures in the areas affected by the warming were about 1 to 2 degrees higher than during the subsequent cold period, the Little Ice Age. In the northern Atlantic, the pack ice withdrew to the north, and the land glaciers partially disappeared. This warming allowed the Vikings to colonise the island of Greenland (since 986), because the Polar Sea was ice-free in both directions and therefore navigable. The myth of a green, fertile Greenland with even viticulture, which is especially spread by climate change deniers, is only a fairy tale. This rumour originates from the time when the navigator and explorer Erik the Red (950-1003) was exiled to Greenland at the end of the first millennium. It was bitterly cold and life was hard there and Erik invented this lie to lure compatriots from Iceland to Greenland.