<P> The concept of separating church and state is often credited to the writings of English philosopher John Locke (1632--1704). According to his principle of the social contract, Locke argued that the government lacked authority in the realm of individual conscience, as this was something rational people could not cede to the government for it or others to control . For Locke, this created a natural right in the liberty of conscience, which he argued must therefore remain protected from any government authority . These views on religious tolerance and the importance of individual conscience, along with his social contract, became particularly influential in the American colonies and the drafting of the United States Constitution . </P> <P> At the same period of the 17th century, Pierre Bayle and some fideists were forerunners of the separation of Church and State, maintaining that faith was independent of reason . During the 18th century, the ideas of Locke and Bayle, in particular the separation of Church and State, became more common, promoted by the philosophers of the Age of Enlightenment . Montesquieu already wrote in 1721 about religious tolerance and a degree of separation between religion and government . Voltaire defended some level of separation but ultimately subordinated the Church to the needs of the State while Denis Diderot, for instance, was a partisan of a strict separation of Church and State, saying "the distance between the throne and the altar can never be too great". </P> <P> In English, the exact term is an offshoot of the phrase, "wall of separation between church and state", as written in Thomas Jefferson's letter to the Danbury Baptist Association in 1802 . In that letter, referencing the First Amendment to the United States Constitution, Jefferson writes: </P> <P> Believing with you that religion is a matter which lies solely between Man & his God, that he owes account to none other for his faith or his worship, that the legitimate powers of government reach actions only, & not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should' make no law respecting an establishment of religion, or prohibiting the free exercise thereof,' thus building a wall of separation between Church and State . </P>

Where does the phrase separation of church and state originate