The simple answer is that historians are arguing about what it is that they are arguing about. Linda Colley’s profoundly influential Britons, 1707-1832: forging a nation, published in 1992, illustrates the point. Beginning with the parliamentary union of England and Scotland in 1707, the book links the emergence of British identity with the creation of a pan-Protestant front and the fight against the Catholic Bourbon France. Although widely praised, Britons was criticised by Irish historians (Thomas Bartlett and Jim Smyth for instance) for Colley’s decision to exclude Ireland from her story –something she admitted to doing in the preface...