The Great Irish Potato Famine of 1845-1850 followed the rapid spread of potato blight, phytophthora infestans, which destroyed several years of Irish potato crops with black rot. Irish peasants had long depended almost entirely on potatoes for food and income to support their families and to pay rent, tithes to the Church of England, and taxes to the Crown. The disaster was deepened by British government policies that sent tons of grain crops out of Ireland despite quantities sufficient to have prevented starvation, and historians have recognized that generations of political and religious oppression of Irish Catholics worsened its effects. More than one million Irish peasants died, hundreds of thousands were evicted from small farms, many were crowded into disease-infested workhouses, and more than 2 million emigrated to other countries, most to the United States, reducing Ireland's population in a few years from more than 8 million to less than 5 million. Those who emigrated to Michigan enriched the area's culture through hard work and left a lasting legacy, while the resolve of survivors eventually contributed to the independent Republic of Ireland.