Plágurnar miklu á Íslandi.
The Medieval Plague did not reach Iceland during the fourteenth century "Black Death" which ravaged the neighbouring countries. Nor did the plague ever become endemic in the country. In the course of the fifteenth century Iceland was, however, visited by two severe plague epidemics. The present article confirms earlier results concerning the course of those epidemics. The first one reached Iceland in 1402 and ravaged the country until early spring 1404. The second one definitely raged during the winter 1494-95, and earlier research is very likely right in assuming that it reached the country in 1494 and receded in 1495. The first epidemic probably spread over practically the whole country; sources indicate that less than 20% of the clergy survived. The second one left the West Fjords peninsula, with probably around 12% of the population, untouched and elsewhere a slightly larger proportion of the clergy seems to have survived this epidemic than the first one. On mortality rates scholars have made only rather vague guesses; the general assumption is that the first epidemic killed about one-third of the population and the second one a little less. On this question two possible sources of data are available, annals and documents indicating the number of deserted farms several decades after the plagues. Both types of evidence are far from comprehensive or exact. When carefully scrutinized, however, they strongly indicate that the mortality rate in the first plague was between 50 and 60% and in the second one probably between 30 and 50%. It is normally assumed that serious plague epidemics spread among humans with the help of rat fleas. The absence of rats in Iceland in the Middle Ages has therefore lead some scholars to doubt that the epidemics in question really were the plague. Others have argued that the plagues prove the existence of rats in Iceland. Our results concerning the extreme mortality rates, and the apparently total absence of recovery among patients, seem to exclude any other disease than the plague. The current assumption that Iceland was without rats until the eighteenth century also seems to be supported by indisputable evidence. Thus the Icelandic plague epidemics may be among the most convincing examples of the plague causing severe epidemics without being spread by rat fleas. In spite of high mortality rates no long-lasting social or economic changes can with any certainty be traced to the plagues. On the contrary, the decrease in population may have helped to prevent the emergence of fishing villages and thus contributed to the long-term stagnation of Icelandic society. The administration of church and state affairs shows little sign of even temporary disruption. Thus the plagues in Iceland demonstrate how smoothly a primitive society with limited specialization could survive a precipitate drop in population.