History of liberalism
The Agreement of the People (1647) [photograph: here] was a manifesto for political change, proposed by the Levellers during the English Civil War. It called for freedom of religion, frequent convening of Parliament and equality under the law.
Isolated strands of liberal thought that had existed in Western philosophy since the Ancient Greeks began to coalesce at the time of the English Civil War. Disputes between the Parliament and King Charles I over political supremacy sparked a massive civil war in the 1640s, which culminated in Charles‘ execution and the establishment of a Republic. In particular, the Levellers, a radical political movement of the period, published their manifesto Agreement of the People which advocated popular sovereignty, an extended voting suffrage, religious tolerance and equality before the law.
Many of the liberal concepts of Locke were foreshadowed in the radical ideas that were freely aired at the time. Algernon Sidney was second only to John Locke in his influence on liberal political thought in eighteenth-century Britain. He believed that absolute monarchy was a great political evil, and his major work, Discourses Concerning Government, argued that the subjects of the monarch were entitled by right to share in the government through advice and counsel.
These ideas were first drawn together and systematized as a distinct ideology, by the English philosopher John Locke, generally regarded as the father of modern liberalism. Locke developed the then radical notion that government acquires consent from the governed which has to be constantly present for a government to remain legitimate. His influential Two Treatises (1690), the foundational text of liberal ideology, outlined his major ideas. His insistence that lawful government did not have a supernatural basis was a sharp break with then-dominant theories of governance. Locke also defined the concept of the separation of church and state. Based on the social contract principle, Locke argued that there was a natural right to the liberty of conscience, which he argued must therefore remain protected from any government authority. He also formulated a general defense for religious toleration in his Letters Concerning Toleration.
Locke was influenced by the liberal ideas of John Milton, who was a staunch advocate of freedom in all its forms. Milton argued for disestablishment as the only effective way of achieving broad toleration. In his Areopagitica, Milton provided one of the first arguments for the importance of freedom of speech: „the liberty to know, to utter, and to argue freely according to conscience, above all liberties“.