It happened in Ireland and was a period of famine, disease and mass emigration between 1845 and a variable date between 1849 and 1852, in which the population of Ireland was reduced between 20 and 25 per cent. Hunger killed some one million people and forced more than a million to emigrate from the island mainly to the United States and Canada. The cause of hunger was a disease caused by the oomycete Phytophthora infestans, which contaminated potatoes across Europe in the 1840s. Although the whole of Europe was affected, a third of the population of Ireland depended potatoes to survive, and the problem was exacerbated by several factors linked to the political, social and economic situation