When Henry VIII changed the status of Ireland from that of a lordship to that of a kingdom in 1541, he unwittingly handed a powerful ideological weapon to his recalcitrant Irish subjects. From the end of the sixteenth century to the time of Daniel O'Connell, Gaelic Catholic literati exploited the concept of the Crown of Ireland to posit Ireland's existence as a separate kingdom, totally independent of England. This ideology was particularly useful in asserting the rights of the Stuarts to the Crown of Ireland, a crown that had existed from time immemorial according to the new orthodoxy. Professor O Buachalla marshals a vast array of historical, literary, iconographical, and cartographical sources to demonstrate the pivotal role of the Crown of Ireland in Gaelic Catholic ideology for three and a half centuries.