This chapter records liberalism’s birth; it considers the emergence of classical liberalism as a philosophical and biocultural phenomenon that, at length, replaced ancient republican values with Late Modern liberal values, which prioritized individual freedom from internal tyranny over and above group freedom from external domination. As herein discussed, England was in the vanguard in establishing a tradition of stable opposition against absolutism—a path thereafter rapidly trod by many Western European states. Western Europe at large trended in this direction, partially as an outgrowth of a century of Enlightenment philosophy, which we emphasize in this chapter for its stage-setting function and preconditioning effects. This era witnessed the publication of several influential Enlightenment tracts: Milton’s Areopagitica (1644) advocating free speech; Locke’s Letter Concerning Toleration (1689) condemning religious and political coercion; and later works of applied political philosophy, such as Trenchard & Gordon’s Cato’s Letters (serialized in the early 1720s) that cast government as a “trust committed by all…to one, or a few.” This conception of governmental compact differed markedly from divine-right-rule. As reviewed in Chap. 12 , the accession of William and Mary to the throne after the Glorious Revolution left England with a bill of rights that consolidated parliamentary gains made in the wake of the English Civil Wars. Nevertheless, in the early eighteenth century, opposition was still being differentiated from treason, and proto-party actors were apt to view one another as foes to be vanquished. Only as England entered into the latter half of the eighteenth century, especially under King George III, did an entrenched Whig opposition party successfully create a framework within which differences could be fought out across recognizably modern ideological poles.