The philosopher John Locke, who lived through the English Civil War, is generally considered to be the father of liberalism; but, the pamphleteer Richard Overton first wrote,
To every Individuall in nature, is given an individuall [sic]property by nature, not to be invaded or usurped by any...; no man hath power over my rights and liberties, and I over no man's
Indeed, these became Locke's main ideas. Nevertheless, Liberalism did not become a specific doctrine until the 19th century. But, the terms "liberal" and "conservative" began to be defined as evidenced with the writings of Overton and Locke. "Liberal" came to mean the restoration of natural rights, limited government, equality before the law, religious tolerance, suffrage, freedom of the press, equality before the law, and low taxes.
Those who believed in the "liberal" ideals were called "levellers" because their beliefs were in response to the "conservatives" who supported the monarchy. These "conservatives" wanted to maintain the rule of the king as well and the power of the upper classes and political privileges. After the Glorious Revolution of 1688, the liberals were able to limit the powers of the new constitutional monarchy, instituting a Bill of Rights, and a parliament. This type of government encouraged the Colonists to write its Constitution with underlying liberal principles, as wel, so that the government of the United States of America was founded on principles that the "levellers" held. It was later in the 1800's that the Progressive Movement began in an effort to make government change its function to meet the needs of society as it changes. From this movement, the new liberalism began to develop.
Shortly before the 1800's, the French Revolution established Liberty, Fraternity, and Equality, giving all men suffrage for the first time in history. This ideological revolution initiated the real possibility of all men being equal, a basic tenet of liberalism. With the ideals of the Enlightenment in the 1800's, further exercise of liberalism came in the form of Cato Letters, written by John Trenchard and Thomas Gordon, promulgated the concepts of freedom of conscience and the evil of tyranny. Important to the French Enlightenment and liberalism were the Baron de Montesquieu and Voltaire, men who espoused the concepts of a constitutional system of government, the right to a fair trial, and the presumption of innocence, all ideas that influenced men from other countries.