K. H. Jackson's The Oldest Irish Tradition: A Window on the Iron Age was originally delivered as the Rede Lecture at the University of Cambridge in 1964. Jackson intended to show that the heroic literature of Ireland, the Ulster cycle of tales, derived from 'pre-historic' oral traditions which flourished before the introduction of Christianity in the fifth century. By closely examining this body of heroic narrative, Jackson attempted to illustrate how different aspects of the social structures, customs, ethos, and material culture in the tales could provide a picture of Ireland in the Early Iron Age.