Abstract: This essay investigates the question of King Arthur's historicity alongside the construction of the British Empire in early modern British history and cultural literary production. In surveying how monarchs co-opted the fantastical lore of Arthur via historical genealogy to consolidate their power, 'Concocting a Seat at the Roundtable' illustrates how Tudor and Stuart monarchs reified engines of dominance not only in their own time, but also in the centuries that followed. (ALM)