The volcanic winter of 536 was among the most severe and protracted episodes of climatic cooling in the Northern Hemisphere in the last two thousand years.[2] The volcanic winter was caused by at least three eruptions of uncertain origin, with several possible locations proposed in various continents. In early AD 536 (or possibly late 535), an eruption ejected great amounts of sulfate aerosols into the atmosphere, reducing the solar radiation reaching the Earth's surface and cooling the atmosphere for several years. In March 536, Constantinople began experiencing darkened skies and lower temperatures.