This article recovers a largely forgotten and quite surprising argument about the origins of political liberty in Britain: that the Norman Conquest, by making possible an extremely powerful absolute monarchy, paradoxically set in motion the historical process which would later lead to the emergence of limited constitutional monarchy. The article shows how the eighteenth-century writer Jean Louis de Lolme initially made this argument to explain the divergent constitutional orders of Britain and France. De Lolme’s hypothesis was then taken up by (...) numerous historians and political theorists. François Guizot and his fellow Doctrinaires, Alexis de Tocqueville, and John Stuart Mill were among the writers who further developed his historical explanation of the British constitution. The liberal philosophy of history in the nineteenth century sprang from De Lolme's account of how absolute monarchy leads paradoxically to constitutional liberty. (shrink)