The ruins of a Cistercian foundation which began in 1193. Its church, one of Ireland's earliest to use the primitive Gothic style, has a magnificent west doorway (1220-1230) with worked mouldings and dentilled friezes. Damaged in the Elizabethan period, the abbey church was restored and served for many years as a parish church. A reconstructed herb garden has around fifty varieties of medicinal plants historically cultivated by the Cistercians.