Trade was greatly interrupted several times during the Crusades (1095-1291) due to wars between Muslims and Christians, and because of Mongolian Invasions, and later because of the Black Plague. It is thought that the Mongols brought the Plague with them from Asia, and devastated the world population from 1347-1351. Almost a third of the world's population was killed by the plague at this time, although the Americas were not touched by the disease at all.