The Union of Scotland and England on 1 May 1707 was – and for some still is – undoubtedly contentious. This essay takes a close look at the language Defoe employed in his History of the Union, the language of persuasion, and perhaps also of propaganda, and in particular at some of the rhetorical figures and strategies he had refined as a journalist and pamphleteer. Some of the language he used provoked a small pamphlet war, in which his very words were flung back at him. In the second part of this essay I consider how Defoe handled outstanding Scottish historical grievances at the time of the Union, by examining his account of one of the most contentious political issues of the day, the Darien disaster, before offering some conclusions about the insights afforded by such a historical linguistic analysis.