Black Protestant churches are those that minister to predominantly African American congregations in the United States. The first black churches were founded by free blacks in the 18th century. Historically black churches have long been the centers of communities, serving numerous important functions. While the religious-meaning system and social organization of these denominations are similar to those found in white evangelical denominations, African American Protestants emphasize different aspects of Christian doctrine, especially the importance of freedom and the quest for justice. Black Protestants tend to be liberal on economic attitudes and conservative on social issues. The seven major Black Protestant denominations are: the African Methodist Episcopal Church, the African Methodist Episcopal Zion Church, the Christian Methodist Episcopal Church, the Church of God in Christ, the National Baptist Convention of America, the National Baptist Convention, USA, Inc. and the Progressive National Baptist Convention, Inc.