Although the potato saved many lives after the Thirty Years' War, it also caused incredible famine in Ireland. In the 1840s, a potato virus broke out which caused wide spread disease and starvation. The diet of the Irish peasants had become so reliable on potatoes that barely any grains were kept for themselves. Almost all of the grain produced in Ireland was exported however this did not affect the famine because most of the peasants did not have enough money to purchase it anyway. By September of 1846, many people were living off of blackberries and cabbage with no way to acquire more food. In the end, nearly one and a half million people were killed by famine and disease related to the failure of the potato crop.