There are more than 2,000 primary religious organizations in the United States, taking a number of different forms including churches, sects, cults, temples, societies and missions. Their origins are wide and derive from many sources. Before the introduction of Christianity from Europe to the United States, Native American religion was disparate, separated by tribes, clans or nations. It was unstructured but in general spirituality was inherent in every aspect of their lives; religion was characterized by a oneness with nature and the intense relationship between the indigenous people and their environment.
In the 17th century a wave of European settlers crossed the Atlantic to escape persecution in their native countries. They found in the United States a freedom to practice their faith but they also brought with them a determination to convert Native Americans to Christianity, as many Europeans believed that the Indians were without religion.
Many religions practiced today descend directly from those the first immigrants of the 1600s, which included practitioners or members of the Christian denomination. Patterns of immigration increase the complexity of religion in the United States; each tended to be most strongly represented in their corresponding colonized areas. For example in New England, British Congregationalists dominated the religious landscape until a later wave of migration by Italian and Irish settlers established Roman Catholicism in the region.
Historically, the United States offered a unique opportunity for those of all faiths to enjoy freedom within the same nation. America was exceptional in its willingness to embrace diverse religions and was the first western nation to be founded predominately by Protestants rather than Roman Catholics. In fact, religious freedom plays a significant role in the history of the United States. As a result of religious oppression in Europe, those who moved to the New World sought a place in which they were free to practice their faith without fear of persecution. This freedom was enshrined in the First Amendment to the Constitution, which stated that: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof." This religious tolerance allowed for the proliferation of many different denominations of the Christian religion.
Evangelism has long been a part of American religious history; this continues today. Where the "word of God" was spread through printed documents and word of mouth in colonial times, in the modern era the "word" is relayed through television and radio broadcasting and other technologies (in the early 1990s, evangelist websites began to proliferate). So-called "televangelists" gained popularity in the 1950s and this continued until the 1980s, when a series of scandals provoked widespread distrust of them.
Historically, Puritanism attempted to purge the Church of England of its unwanted Roman elements. Originally, 900 Puritan colonists arrived in Massachusetts Bay; by 1640, they were 17,800 in number and in 1700, this had grown to 106,000. It was characterized by self-imposed isolation, religious exclusivity and the belief that people were individually accountable to God. The Puritans were responsible for the first free schools in America. They established the first American college, Harvard, in Cambridge, Massachusetts. Later on, Puritanism would lead to the Baptist and Congregationalist movements.
By the end of the 19th century, Roman Catholicism was the largest denomination in the United States. This was due to the sheer size of the population of immigrants who originated from Catholic nations. Its members grew following an aggressive campaign of recruitment, which was meant to counter Protestant sects. American Catholicism demanded a distinctive lifestyle and placed high standards on the members of its church. However, its stronghold gave way to a pluralistic society which began in the 1880s.
Different denominations attract membership according to their language and ethnicity. For example as late as 1916, nearly half of all Catholic services were held in a language other than English. In 1880 in New York alone, there were 80,000 Jewish immigrants. By 1910, this had increased to more than one million. They, like the Protestants, developed institutions that appealed to new immigrants.
By the 21st century America was a country of religious tolerance that extended to numerous faiths including great world religions such as Hinduism, Buddhism and Islam as well as the innumerable offshoots of Christianity. This tolerance, however, witnessed its greatest challenge in the wake of the infamous terrorist attacks on U.S. targets in September 2001.