l Ireland's population plummeted by 20% to 25% during the famine.

l The potato was first introduced to Ireland as a garden crop of the gentry in the mid-1600s. But the first two decades of the following century it had became a base food of the poor, especially in winter.

l The large dependency on this single crop was one of the reasons why the emergence of Phytophthora infestans – potato blight – had such devastating effects in Ireland, but far less in other European countries.

l More than three million Irish people were totally dependent on potatoes when the famine began in 1845.

l The fungus is believed to have first arrived in Ireland in 1844, and has been traced to Mexico.

l It is believed it spread initially through North America, and diseased potatoes were carried across the Atlantic in ships.