The 17th century was a time of revolution in European religion, science and philosophy. New ideas clashed with old, and where religion was tied up with politics and other vested interests, the conflict was often violent. Islam and Judaism prevailed in certain countries, but the most common religion in Europe was Christianity, which comprised many factions in uneasy and often antagonistic coexistence.

The Legacy of the Reformation

While the Greek Orthodox Church held sway in Greece and the Balkan states, the Reformation of the 16th century had divided the rest of Europe broadly into Catholic and Protestant. By breaking the moral, intellectual and political grip of the Roman Catholic Church, the Reformation made possible new forms of government and gave people a choice of religion. In England, the costs of having a choice included civil war between the Catholic Stuarts, who believed in the divine right of kings, and the Puritan parliament, who believed the king should obey not dictate the law. Religious strife continued all over Europe, feeding the political disputes between, for example, Spain and England, and exacerbating the economic rivalry between Spain and the Netherlands.

Catholicism

Although Protestantism spread rapidly, first guided by Luther and later also by Calvin, Catholics remained in the majority. Led by the Jesuits and supported by powerful kings and statesmen such as Richelieu, the Counter-Reformation sought to re-establish papal control over doctrine and stamp out Protestant “heresy.” However, Jesuit authority was challenged by other orders such as Franciscans and Dominicans and by Catholic sects such as Huguenots, Quietists and Jansenists. The Church persecuted these sects because it felt threatened by their more individualistic approach to religious belief and moral responsibility.

Protestantism

State Protestantism was similarly complicated by internal division. Lutheranism spread across Germany and Scandinavia, but Calvinism gained more influence in Switzerland, France, the Netherlands and Scotland, with its emphasis on predestination, obedience and the imminent Second Coming. Both Luther and Calvin demanded total conformity to their church and all it stood for, and persecuted dissenting sects like Anabaptists, Mennonites, Socinians and Pietists. In England, the Puritans aimed to cleanse the state religion of lingering Catholic tendencies, but were themselves divided among groups such as Quakers, Unitarians, Presbyterians and Congregationalists, who all wanted to organize their churches in different ways. Many Puritans were among the various groups of dissenters who left Europe to pursue religious freedom in the New World.

Witchcraft and Paganism

Following the turbulence of the Reformation, religious zealotry combined with local feuds and rivalries to find a common target in the persecution of witches -- a catch-all term for almost any social misfit, whom the Church labeled allies of Satan. Before the end of the 17th century, between 50,000 and 100,000 "witches" had been executed, most of them in Germany, Switzerland and France. By then, however, witch-hunting became less hysterical, scientific rationality became more fashionable, and interest grew in studying pre-Christian cultures, such as Greek and Roman mythology, paganism and Druidism.

Islam and Judaism

The Turks introduced Islam to the Balkan countries they conquered, where it existed alongside Orthodox Christianity. In Spain, however, Muslims were severely persecuted under the Catholic Hapsburg kings and the Inquisition. There were Jewish communities in most European countries, with the largest -- accounting for 450,000 people -- in the Netherlands, Poland and Lithuania. Persecution by Christians in southern Europe, particularly under the Spanish Inquisition, forced them north and east. According to the American Council for Judaism, Jews seeking a new start, free of persecution, settled in the Dutch colonies in the Americas, first in Brazil and subsequently, through trade, in the New Netherlands, present day New York.