It is well known that sixteenth- and seventeenth-century Welsh and Breton scholars nurtured a belief in the Prophecy of Merlin, which foretold their peoples’ deliverance from foreign servitude. Yet recent historical scholarship has not explored the implications of the prophecy with regard to the explosion of interest in ecclesiastical history and antiquarianism in early modern Wales and Brittany. As Geoffrey of Monmouth declared in the twelfth century, ‘Only when they had on show again the relics of all their other saints, which had been hidden away because of the pagan invasion, would they reoccupy their lost kingdom’. This prophecy, widespread in both early modern Wales and Brittany, helps explain the context and function of sacred historiography in these two provinces.

J. G. A. Pocock states that when attempting a comparative history between the different areas of the British Isles, or Atlantic archipelago:

Yet, neither Pocock nor other recent historians of the Atlantic archipelago include Brittany in their comparative studies. This seems rather paradoxical since Pocock's statement applies equally well to Brittany. It is precisely during the ‘Arthurian’ moment of Geoffrey of Monmouth's Historia that the legendary connection between Wales and Brittany commenced.