and regulations, despite the autonomy of the church. Some denominations are members of a national alliance of churches of the World Evangelical Alliance. Some evangelical denominations operate according to episcopal polity or presbyterian polity. However, the most common form of church government within Evangelicalism is congregational polity. This is especially common among non-denominational evangelical churches. Common ministries within evangelical congregations are pastor, elder, deacon, evangelist and worship leader. The ministry of bishop with a function of supervision over churches on a regional or national scale is present in all the Evangelical Christian denominations, even if the titles president of the council or general overseer are mainly used for this function. Divisions and controversies Today there is a wide diversity of Christian groups, with a variety of different doctrines and traditions. These controversies between the various branches of Christianity naturally include significant differences in their respective ecclesiologies. Christian denominations A denomination in Christianity is a generic term for a distinct religious body identified by traits such as a common name, structure, leadership, or doctrine. Individual bodies, however, may use alternative terms to describe themselves, such as "church" or "fellowship". Divisions between one group and another are defined by doctrine and church authority; issues such as the nature of Jesus, the authority of apostolic succession, eschatology, and papal primacy often separate one denomination from another. Groups of denominations often sharing broadly similar beliefs, practices, and historical ties are known as branches of Christianity. Individual Christian groups vary widely in the degree to which they recognize one another. Several groups claim to be the direct and sole authentic successor the church founded by Jesus Christ in the 1st century AD. Others, however, believe in denominationalism, where some or all Christian groups are legitimate churches of the same religion regardless of their distinguishing labels, beliefs, and practices. Because of this concept, some Christian bodies reject the term "denomination" to describe themselves, to avoid implying equivalency with other churches or denominations. The Catholic Church and Eastern Orthodox Church believe that the term one in the Nicene Creed describes and prescribes a visible institutional and doctrinal unity, not only geographically throughout the world, but also historically throughout history. They see unity as one of the four marks that the Creed attributes to the genuine Church, and the essence of a mark is to be visible. A church whose identity and belief varied from country to country