The Plymouth Brethren are a conservative, low church, nonconformist, Evangelical Christian movement, whose history can be traced to Dublin, Ireland, in the late 1820s, originating from Anglicanism. Among other beliefs, the group emphasizes sola scriptura, the belief that the Bible is the supreme authority for church doctrine and practice over tradition. Apart from a few (mostly small) exceptions, such as the Churches of God, Brethren churches are all independent, self-governing, local congregations with no central headquarters, although there are a number of seminaries, missions agencies, and publications that are widely supported by Brethren churches and which help to maintain a high degree of communication among them. They generally see themselves not as a denomination, but as a network, or even as a collection of overlapping networks, of like-minded independent churches.