The 17th century was torn by witch-hunts and wars of religion and imperial conquest. Protestants and Catholics denounced each other as followers of Satan, and people could be imprisoned for attending the wrong church, or for not attending any.
All publications, whether pamphlets or scholarly volumes, were subject to prior censorship by both church and state, often working hand in hand. Slavery was widely practiced, especially in the colonial plantations of the Western Hemisphere, and its cruelties frequently defended by leading religious figures.
It was inevitable that sooner or later many people would begin to grow tired of the repression and warfare carried out in the name of absolute truth. In addition though Protestants had begun by making powerful critiques of Catholicism, they quickly turned their guns on each other, producing a bewildering array of churches each claiming the exclusive path to salvation. It was natural for people tossed from one demanding faith to another to wonder whether any of the churches deserved the authority they claimed. People lived in rural areas only producing what was needed to survive. As scientific thought emerged, more influence on people’s ideas and social norms expanded, the way of thinking and living changed and people moved to urban areas to work and live.
The Enlightenment consisted, in essence, of the belief that the expansion of knowledge, the application of reason, and dedication to scientific method would result in the greater progress and happiness of humankind.
Although the intellectual movement called "The Enlightenment" is usually associated with the 18th century, its roots in fact go back much further. This is one of those rare historical movements, which in fact named itself. Certain thinkers and writers, primarily in London and Paris, believed that they were more enlightened than their compatriots and set out to enlighten them, they believed that human reason could be used to combat
Bibliography: Manifesto of the Communist Party, 1848 Marxists Internet Archive