 An early incarnation of Welsh rarebit was being made in medieval times, and by the middle of the 15th century rarebit was considered a national dish.The acid soil of Wales meant that the milk produced by their cattle created a soft cheese, which was not as good for roasting, so Welsh people would trade for harder cheeses such as Cheddar.The best-known Welsh cheese is Caerphilly, named in 1831 but made long before that.