The United Church of Christ is a mainline Protestant Christian denomination that formed in the United States in 1957 with the joining of the Congregational Christian Churches and the Evangelical and Reformed Church. Like their Congregational predecessors, United Churches of Christ typically hold that the local congregation is autonomous from ecclesial hierarchy and has a freedom to self-governance. This concept of self-governance is traced back to the origins of Congregationalism in 16th- and 17th-century England and the Protestant Reformation. Congregationalism developed as one of branches of English Puritanism. It experienced its most significant growth in the United States as the separatist "Pilgrims" of the Plymouth Colony and the non-separatist Puritans of the Massachusetts Bay Colony. Like many of the other Christian religious traditions, Congregationalism also experienced significant growth during the 1730s and 1740s during the Great Awakening. Later, a general liberalizing began to occur within Congregationalism and some members even left to join Unitarianism. Eventually, Congregational churches began to unify with other denominations, including what has now become the United Church of Christ. Today, only a few associations of churches maintain the Congregational name, even though the tradition continues. The United Church of Christ is active in ecumenical movements and tends to favor more liberal or progressive stances on social issues including women's rights and gay rights.