The primary cause of the Irish Potato Famine, which occurred between 1845 and 1852, was the widespread failure of the potato crop due to a fungal disease known as late blight. Potatoes had become a staple food for a significant portion of the Irish population, and their sudden failure led to catastrophic food shortages. Additionally, the British government's inadequate response, land ownership issues, and economic policies exacerbated the crisis, leading to massive starvation, disease, and emigration. Approximately one million people died, while another million fled Ireland, significantly impacting its demographic and cultural landscape.