During Iolo Morganwg's lifetime Britain was obsessed with literary forgery. This book reveals the unexpected connections and hidden influences behind Britain's most successful (and hence, perhaps, least visible) Romantic forger. Quoting extensively from unpublished manuscripts, it explores Iolo's own strongly-held ideas about the Truth-historical, literary and religious-and shows how he responded to the work and the criticism of both James Macpherson and Thomas Chatterton. It also shows how, after death, his ideas affected the Breton writer Hersart de La Villemarqúe, whose ordination as a Iolo-style bard in 1838 helped to bring about a Celtic cultural revival in Brittany.The subject sits neatly at the intersection of two currently popular critical domains: British Romantic literary forgery, and Celticism, a subject which explores the development of mutual contact between the Celtic-speaking regions, as well as the complex relationship between the peripheries and the centre.