On the Eve of May Day, one of the great Celtic feasts, the people, moving in lines, were wont to urge their cattle between two fires that they might be purified and preserved during the coming year. And since nothing dies harder than tradition, it may well be that, long after their significance was forgotten, these ancient ceremonial line-movements developed into the forms of the 'Rinnce Fada' and 'The Hey' still danced in the Ireland of today. For over three centuries after the Tudor wars everything Irish was forbidden, and dancing, like all the other peaceful arts, suffered a decline. Some dances were irretrievably lost, but, largely by the efforts of the Gaelic League, others have been recovered and revived. Step notations and music for several of these, including the famous 'Rinnce Fada', are given here with four coloured plates of costumes. Peadar O'Rafferty, founder of Lambeg Irish Folk Dance Society and for many years instructor to Malone Training School, was a pioneer of the folk-dancing revival in Belfast. His son, Gerald, has frequently acted as adjudicator at Irish musical festivals.