SNIPPET: Ireland's agriculture had failed frequently in the century and a half leading up to the Great Hunger. Failures, some leading to significant death tolls, occurred in 1708-09, 1725-29, 1740-41, 1745-46, 1753, 1766, 1769-70, 1772-73, 1782-84, 1795-96, 1800-01, 1817-18, 1821-22, 1830-31, 1835, 1839, and 1842 . The greatest of these occurred in 1740-41, due to extremely cold weather, and produced a famine that killed as many as 400,000 people -- a level proportionate to the Great Famine of 1845-52. Ireland's Great Famine (1845-52) was multifactorial. Ireland's population had doubled from 4,000 in 1800 to over 8,000 in 1845, making it the most densely populated nation in Western Europe. Owing to British colonial policies, the vast majority of the population was so poor that they were dependent upon the potato as their main source of food. Starting in 1845, a mysterious blight destroyed successive potato crops between 1845 and 1852. Lastly - an indifferent British government failed to respond to the crisis, resulting in more than a million deaths and more than a million emigrants. The potato was native to South America, in the region of the Andes. Sir Walter RALEIGH is credited with introducing the potato to Europe, planting them on his lands in Ireland in the 1580s. The potato took hold in Ireland for a number of reasons. The Irish climate is particularly well suited to potato growth. Potatoes will grow almost anywhere -- rocky soil, wet bogs or on hills. They are easy to cultivate and produce high yields -- up to six tons on a single acre of land. Other advantages include their easy preparation (no milling, as with grain), lack of disease (before 1845), and extraordinary nutritional value. This was made clear by the many contemporary accounts of the Irish poor as being exceptionally strong and healthy. Irish males on the eve of the Famine were on average the tallest in Europe, per Edward T. O'DONNELL, in his book, "1001 Things Everyone Should Know About Irish American History." At first the potato was a food enjoyed only by the Irish gentry. But over the course of the 1600s, the British reduced the majority of the Irish people to the status of peasant farmers on small plots of rented land, who in turn devoted increasing acreage to the growth of potatoes that they ate as a supplement to their diet of oats, grains, and dairy products. In the 18th Century, as conditions for the Irish peasants worsened, it became more and more of a staple crop, especially during the winter. On the eve of the Famine, perhaps a many as 60% of the Irish people were solely dependent on the potato as their main source of food. It must be pointed out, however, than on the eve of the Famine potatoes constituted just 20% of Ireland's annual agricultural output. Irish farmers of all ranks grew oats and grains alongside their potatoes. They also raised cows, goats, pigs, and chickens. Peasant farmers, however, ate very little grain, bacon, meat, or eggs. Instead, these p! roducts, along with some potatoes, were sold for cash to pay their rents. Phytophthora infestans ("late blight") was a deadly fungus spread rapidly by spores in air or water. It originated in Mexico, appeared in America in the fall of 1843, and then made its way to Western Europe by way of transatlantic ships. Irish farmers told of it striking overnight, leaving blackened leaves, gooey inedible tubesr and a sickening stench. The first reports of disease among the potatoes of Ireland came from the Botanic Garden in Dublin in August 1845. By September, the blight spread to farms in the northeast, eventually destorying one-third of the potato crop. In 1846, the blight reappeared in June and spread at a rate of 50 miles per week to all 32 Irish counties, destroying almost 90% of the crop. Although the loss of just 30% in 1847 seems small, it was equally devastating because farmers had planted so few potatoes. Half the potato crop of 1848 fell to the blight. Between 1849 and 1852, smaller, localized outbreaks occurred, primarily in the south a! nd west. The blight was not confined to Ireland. The first reports came from Belgium in June 1845. By September it appeared not only in Ireland, but also in parts of England, Scotland, France, the Netherlands, Germany, Scandinavia, and Russia.