Land holdings were so small and of such poor quality that families could support themselves only through the planting of potatoes. To know why so many Irish families subsisted on such small plots of land, one must re-examine the ‘Penal Laws’ which were introduced in 1690 after the Catholic supporters of James II were defeated by the Protestant forces of William of Orange. These were laws that banned Catholics from an education, religion, professions, forbade Catholics from possessing arms or owning a horse worth more than £5 etc. The majority of Irish did not have money to purchase food and were fundamentally human slaves to their landlords. The Truth Behind The Irish Famine: http://www.jerrymulvihill.com