Note: this page is something that has as much relevance in the period of time the Saint Muhammad timeline is on as of the moment as in the year 2.013 in the same timeline. The page is thusly updated as soon as possible. The current date is 950 AD.
Christianity is a monotheistic religion (or group of religions) based on the life and teachings of Jesus Christ. Together with Judaism, Samaritanism and several minor heresies, it is an Abrahamic religion. It is mostly differing from the Judaic religion in several minor practises and the fact that besides the Old Testament, there's a series of books, the New Testament, that are also considered canonical.
The mainstream Christian belief is that Jesus is the son of God and saviour of humankind. Christians therefore refer to Jesus as Christ or the Messiah. However, the status of God is controversial and divides even the most adherent communities of Christianity (the Nestorian Faith in Ctesiphon and the Patriarchate of Constantinople) , and has caused the main schisms of history (the Nestorian schism that took away Mesopotamia and Syria due to Nestorius believing on Jesus and God being separate entities, and its antithesis, Miaphysitism, which stated that they were a single being and took away Egypt and Palestine).
There are hundreds of denominations, or "Faithts", of Christianity. However, four provide the majority of the Christian faith; the Chalcedonian Faith (most often considered mainstream), the Coptic Faith (based in Alexandria and Miaphysite), the Faith of the East (based in Ctesiphon, and Nestorian) and the Medinan Faith (based in Mecca). While these Faiths bicker amongst theological disputes (with the Medinans and Nestorians being especially considered heretical) but they all consider each other more valid than most of the other religions, and often cooperate (with the Chalcedonian Church, for example, having sanctified Muhammad, the founder of the Medinan Faith, in the early XIII Century).
List of Major Denominations
The Chalcedonian or Catholic Faith
The Chalcedonian Faith was formed in the Council of Chalcedon in 451, which the Faiths at Aram, Syria, Egypt and Palestine all rejecting the notion. Christianity was split into two; the very united Chalcedonian Faith and what is called by many the Oriental Orthodox Faith.
The Chalcedonian Faith has five patriarchates (Rome, Constantinople, Antioch, Jerusalem and Alexandria) of which Rome is generally considered the most important, of which only Rome and Constantinople are in mostly Chalcedonian nations, and of which only Rome, Constantinople and Jerusalem are in mostly Chalcedonian regions.
The Chalcedonian Faith is also divided among the Westerners (Calling themselves the Universal Faith) and the Easterners (Calling themselves the True Faith). Often, the Patriarch of Constantinople and the Pope at Rome ague heavily, just to return to present state once that their nation has been threatened at a war. This happened for the longest time in the XVIII Century, and has repeated itself once or twice.
The Oriental Orthodox Faiths
The Faith of the East or Nestorianism
Following a Greek patriarch, Nestorius', teachings, the Nestorians argue that God and Jesus are two different minds, which subtracts some divinity from Jesus. While Nestorius was Greek, his argument was popular amongst Christians in Erak, heavily influenced with Zoroastrian and Manichaean teachings. Nestorianism was the official faith of the Empire of Aram from 655 until its dissolution, and the Pope of the Faith at Babylon-Ctesiphon became very influential from then on, crowning a "Emperor of Aram" amongst the most powerful of the ex-Aramean states every few years.
The Faith of the East is centred on the Pope of Aram, who officially is settled in Babylon but de facto always is in Ctesiphon/Seleucia/Veh Ardashir. The Pope in Aram's second in command is the Patriarch, who rules from Antioch. Nestorianism is thusly the dominant Faith in the Aramaic Empire (excepting for Palestine, where the Chalcedonian Melkites dominate, the areas of Anatolia, where Orthodox Chalcedonianism is practised, the extreme north, where most are Jews or Armenian Christians, and the eastern fringes, mostly Mandaic and Zoroastrian) and the northern parts of the Middle East. Every single king at Aram except four (Musa I, Bassi, Musa II and Kalaba of Aram), of which only two had any control out of Soqotra. The Faith of the East also spreads east, forming 30-35% of Persia's population, close to 80% in areas like Bukhara, and spreading eastwards, even into China. Nestorianism in China (where it is known by its Oriental name, Jingjiao (景教), and where it has three metropolitan sees in two different Chinese dynasty-kingdoms, the Tang (Southern, in Guangzhou, and Northern, in Chang'an) and the Zhü (in Luoyang)). The Faith of the East also exists in the southwestern coast of India, where the Saint Thomas' Faith exists.
Da'huyi (ܟ݂ܽܘܐ, lit.[the] Pure) is the term for a mystic sect formed in southwestern India and Parsistan from Nestorianism, Zoroastrianism and Hinduism mixing together. Da'huyi seeks to directly connect with God by the repetition of several mantras and the "purification of the heart and its turning away from all other things but God".
The Oriental or Coptic Faith
The Copts have developed a mildly Syncretic religion; Egyptian beliefs have heavily influenced Christianity on the area, although Christianity is still very recognisable in the Egyptian form. Egyptians are strongly Monophysite, thinking that God and Jesus are the same thing both in form and mind as well as inspiration. The argument of Miaphysitism originally came as a way of fighting against Nestorianism; however, it eventually became even more radical, to the point where it now is considered the antithesis of Nestorianism. Even then, both Faiths are considered parts of the Oriental Orthodox Faith.
Coptic Christianity is widely popular on northern Egypt and contests with Egyptian Neo-Paganism as the most popular religion in Southern Egypt. Beyond its homeland of Egypt, the Coptic Faith is the largest stable faith in the African continent (the Universal Chalcedonians, locally based on Carthage, is often divided amongst several idelogies like Donatism and other "True Believers"). The dioceses of Miaphysite Christianity move southwards along the Nile, in which the Primate in Axum and the Metropolitan in Dongola, both in the former Axumite Confederation and now in Nubia (for one) and the Axumite Kingdom (for the other). The Pope at Alexandria also holds sway over minor diocese in Lebanon (although the Maronites, a different denomination, predomine there) and Palestine (although the Melkites, Chalcedonians, are the majority).
The Medinan or Muhammadic Faith
The Medinan Faith is relatively recent, originating not from a schism but from an invention, in Mecca in AD 610. It has since rejected the Chalcedonian notion, but is not in itself a Oriental Orthodox faith in the most technical of cases.
The Medinan Faith is especially revolutionary in its ideology. According to it, God sent a later (and far more secondary) saviour, Muhammad, to correct the errors that had risen in his Kingdom. It basically makes the founder of the church, Muhammad, almost divine, and second only to Jesus. The Church has been heavily criticised by several of the other Christian denominations for this heresy. Besides that, the Medinan Faith has a well-defined angelic hierarchy, with Gabriel second in command only to God and having taken several of the other two main archangels (Michael and Raphael)'s characteristics and jobs. This is because Muhammad claimed that he was visited by Gabriel. The Medinan Faith also recognises the true hierarch of the Christian faith to be in Mecca (in the Kaaba Cathedral) and states that, while the Pentrachy used to be the true authority in Christianity, it has been corrupted. Several other minor practises are also used that difference it from other faiths. Besides that, Medinan Christianity resembles Miaphysitism to a level.
Medinan Christianity is only centred on Arabia and has barely made any inroads out of it. This is in part due to its affiliation to Medinan politics; the two royal families are pseudo-divine and the kingdom is considered "God's Kingdom". However, recently Medinan Christianity has been losing its political connotation after the loss of Medinan independence to Aram and later on the division of the areas.
Other Minor Denominations
The Gbara Faith
Gbara Christianity developed from the Qallu and the Uka'ma imported to Iraq, converting to Nestorian Christianity while retaining a lot the original African characteristics. For example, Gbara Christianity doesn't have a Pope, but instead has a Gbara, or council of elders (hence its name), who rule upon theological disputes.
Gbara Christianity is practised by the ruling factions of Socotra, almost entirely Qallu, and has been moving down the scale of the Soqotri aristocracy as the Qallu are South Arabised and the Soqotri are somewhat Africanised.