Potatoes were introduced to Ireland from the Americas by Walter Raleigh.
There was plenty of food during the Irish famine , but it was all sold to pay exorbitant rents to absentee land Lords. Potatoes were the staple food because they were relatively easy to grow and didn't fetch a high price at markets anyways, so once the blight destroyed the potato crop, the choice became do I eat the food that I use to pay rent , and become homeless and then starve , or pay my rent with my crops and starve and then be too hungry work the land to pay rent, and so become homeless.
Not great choices .
