In Ireland there was a dependence of a large section of the population agriculture and the potato crop. The famine was the result of successive crop failures and the insufficient and ineffective relief for stopping the outbreak of starvation and disease. The famine was the most tragic and significant event in Irish history and one of the worst human disasters of the nineteenth century. Ireland depended on the potato as a staple crop after 1800. Population increased rapidly and reached eight million by 1841, two-thirds of who depended on agriculture. The Irish depended on the potato and the failure of the potato crop in 1845 was disastrous. The crop failed again in 1846, 1847, and 1848. By 1851, the population of Ireland had been reduced by more than two million due to starvation, disease, and emigration to Britain and North America.