"The Black Death", which rolled over Europe from 1347 to 1350, was the greatest human disaster the world has ever seen from the sixth up to the end of the nineteenth century. This horrible disease, spreading out with unusual speediness, was an effect of the very primitive hygienic habits of Middle Age society. Bacilli of the plague were transferred by black rats, by their fleas to be exact. From a medical point of view, the bacillus Pasteurella Pestis caused the most common form of the plague. The visible effects of the infection were huge blisters, rising just under the groin of a sick person. Additionally, on a skin of such a person, very often, black spots appeared, caused by inner bleeding. The agony usually persisted usually for a few days [Davies, 1998, 241], The infection appeared in Middle Asia and was transferred with terrible speed towards Europę. In 1346 the plague appeared in Kaffa on the Crimean Peninsula. The Tatars besieged this town. They used a "bacteriological weapon" - the bodies of dead comrades, infected by the plague, which were thrown beyond the walls of the city and thus transferred this infection among its inhabitants. The defenders of Kaffa ran away to Sicily. At the beginning of 1348 the plague had spread over almost the whole Italy. By 1350, the plague had entered Scotland, Denmark and Sweden and finally Russia, through the hanzeatic towns. As historians estimate, the number of victims of the plague was about 35% of the population of medieval Europę. In England 1.4-2 million people died, in France - 8 million, and about 30 million in Europe.(fragment of text)