Terminology and qualification
Some groups included on this list do not consider themselves denominations. For example, the Catholic Church considers itself the one true church and the Holy See as pre-denominational. The Eastern Orthodox Church also considers itself the original Christian Church and pre-denominational. To express further the complexity involved, the Catholic and Eastern Orthodox churches were historically one and the same, as evidenced by the fact that they are the only two modern churches in existence to accept all of the first seven ecumenical councils, until differences arose, such as papal authority and dominance, the rise of the Ecumenical Patriarchate of Constantinople, the fall of the Western Roman Empire, the continuance of emperors in the Eastern Roman Empire, and the final and permanent split that occurred during the Crusades with the siege of Constantinople. This also illustrates that denominations can arise not only from religious or theological issues, but political and generational divisions as well.
Other groups that are viewed by non-adherents as denominational are highly decentralized and do not have any formal denominational structure, authority, or record-keeping beyond the local congregation; several groups within the Restoration Movement fall into this category.
Some groups are large (e.g. Catholics, Orthodox, Lutherans, Anglicans or Baptists), while others are just a few small churches, and in most cases the relative size is not evident in this list except for the denominational group or movement as a whole (e.g. Church of the East, Oriental Orthodoxy, Lutheranism or the Latter Day Saints). The largest group is the Catholic Church with more than 1.3 billion members. The smallest of these groups may have only a few dozen adherents or an unspecified number of participants in independent churches as described below. As such, specific numbers and a certain size may not define a group as a denomination. However, as a general rule, the larger a group becomes, the more acceptance and legitimacy it gains.
Modern movements such as Christian fundamentalism, Pietism, Evangelicalism, the Holiness movement and Pentecostalism sometimes cross denominational lines, or in some cases create new denominations out of two or more continuing groups (as is the case for many united and uniting churches, for example). Such subtleties and complexities are not clearly depicted here.
Between denominations, theologians, and comparative religionists there are considerable disagreements about which groups can be properly called Christian or a Christian denomination as disagreements arise primarily from doctrinal differences between groups. As an example, this list contains groups also known as "rites" which many, such as the Catholic Church, would say are not denominations as they are in full papal communion, and thus part of the Catholic Church. For the purpose of simplicity, this list is intended to reflect the self-understanding of each denomination. Explanations of different opinions concerning their status as Christian denominations can be found at their respective articles.
There is no official recognition in most parts of the world for religious bodies, and there is no official clearinghouse which could determine the status or respectability of religious bodies. Often there is considerable disagreement between various groups about whether others should be labeled with pejorative terms such as "cult", or about whether this or that group enjoys some measure of respectability. Such considerations often vary from place to place, or culture to culture, where one religious group may enjoy majority status in one region, but be widely regarded as a "dangerous cult" in another part of the world. Inclusion on this list does not indicate any judgment about the size, importance, or character of a group or its members.