After European settlement, religious history began more than a century before the British colonies became the United States of America in 1776. Some of the original settlers were men and women of deep religious convictions. The religious intensity of the original settlers diminished to some extent over time but new waves of 18th-century immigrants brought their own religious fervor across the Atlantic. In addition, the nation's first major religious revival in the middle of the 18th century injected new vigor into American religion.
Wave after wave of ethnic groups from Europe (as well as other parts of the globe) brought along their traditional churches—some, especially the English and the German Americans brought along multiple Protestant denominations, as well as Catholicism. Several colonies had an "established" church, which meant that local tax money went to the established denomination. In general, the colonial governments were little involved in religion, and many denominations and sects flourished. Freedom of religion became a basic American principle, and numerous new movements emerged, many of which became established denominations in their own right. The heavy influx of immigration in the 19th and 20th century reinvigorated religion; in many cases, the immigrants became much more religious than they had been in the old country in order to assert their new complex identity. As Europe secularized in the 20th century, the Americans largely resisted the trend, so