Christianity (from the Ancient Greek translation Χριστός, Christos of the Hebrew מָשִׁיחַ, Mašíaḥ, meaning "the anointed one" and the Latin suffixes ian and -itas) is a monotheistic religion based on the life and teachings of Jesus Christ as presented in the New Testament. Christianity is the world's largest religion, with approximately 2.2 billion adherents. Most Christians believe that Jesus is the Son of God, fully divine and fully human, and the savior of humanity prophesied in the Old Testament. Consequentially, Christians refer to Jesus as Christ or Messiah.
Worldwide, the three largest groups within Christianity are the Catholic Church, the Eastern Orthodox Church, and the various denominations of Protestantism. The Roman Catholic and Eastern Orthodox patriarchates split from one another in the schism of the 11th century, and Protestantism came into existence during the Reformation of the 16th century, splitting from the Roman Catholic Church.
Christianity in 1632
By 1631, Christianity had spread thoughout Europe, though some of the remoter Scandinavian peoples were, at most, only nominally Christian. European states, including the German mini-states and free cities, generally had established Christian faiths under the principle that the ruler(s) of an area, even one as small as a village or two under the jurisdiction of an imperial knight, got to determine the faith of its residents. Within the Holy Roman Empire, this was only supposed to apply to Catholicism and Lutheranism, but Calvinist rulers also tended to impose their faith.
Outside of Europe and areas colonized by European powers, Christianity was primarily Eastern Orthodox. Catholicism had been introduced into Japan in the middle of the 16th century, and still had a presence in 1631, even though the Tokugawa shogunate had banned it in 1614, and there had been earlier, less effective, bans in some areas. However, Japanese Catholicism, especially as practiced by ordinary people in Japan itself, had accumulated a number of beliefs and practices from Buddhism and Shintoism.
The arrival of Grantville sent waves through 17th century European Christianity. For a start, there were questions about how to explain the Ring of Fire itself, given that the age of miracles was supposed to be long past. The American versions of Catholicism, Lutheranism, Anglicanism, and Calvinism were different -- sometimes quite different -- from their down-time counterparts, and most of Grantville's Protestant churches were from varieties of Protestantism that had developed after the 1630s.
Perhaps the strongest effect was caused by late-20th-century American ideas about separation of church and state, religious freedom, religious tolerance, and even religion itself. Once Grantville established contact with communities outside the Ring of Fire, it quickly became obvious that the town had no official -- or even preferred -- church, and that that was seen as normal even by the churches themselves. Thanks to Grantville's libraries, it was soon known that, by 2000, even those European states that still had reigning monarchies and officially established or recognized churches had abandoned the notion of attempting to impose or enforce religious uniformity or orthodoxy -- and that the ruling houses that had not abandoned it had not survived.
Christianity in Heirs of Alexandria
The conversion of Hypatia of Alexandria to Christianity in the 5th century set the faith on a different course than it had followed in the OTL. One difference was a decreased emphasis on dogmatism and hunting for heretics. By the 1530s, western Christianity had become sub-divided into two primary creeds. One, commonly known as "Petrine" after St. Peter, was based on the teachings of Hypatia and John Chrysostom. The other, commonly known as "Pauline" after St. Paul, was based on the teachings of St. Augustine. There was also a Gaelic creed with its own history and doctrines, which was not given to stringent theology. Christianity had not yet penetrated the Scandinavian peninsula to any significant degree outside of a few areas controlled by the Pauline military order known as the Knights of the Holy Trinity.
As of the later 1530s-early 1450s, the Petrines appeared to predominate in most of Italy (including Venice), and the Iberian peninsula, and to have a relatively large following in Aquitaine. The Paulines appeared to predominate in central and northern Europe. Gaelic Christianity was strongest in the Celtic/Norse League of Armagh.
In general, the Petrine creed was known for a more tolerant approach to non-Christian beliefs and practices, and even non-human beings and entities that were recognized as beings of good will. The Pauline creed was generally known for intolerance of non-Christians. In practice, both "Petrine" and "Pauline" were umbrella terms; there could be, and was, considerable variation among individual followers of both creeds. Each branch had a religious order that more-or-less exemplified its teachings. For the Paulines, this was the Servants of the Holy Trinity; for the Petrines, it was the Order of Hypatia. The Order of Hypatia was open to both men and women, who were known as "Siblings".
As of the later 1530s-early 1540s, the differences between the creeds did not appear to have reached the level of a true schism. The acknowledged leader of the Church was the Grand Metropolitan of Rome, who appears to have been a Petrine. It is not clear if the Grand Metropolitan was always, or even usually, Petrine. Also, it is not clear if there was an official or acknowledged head of the Pauline wing of the Church.
Nestorian Christianity existed in and around the Ilkhanate and the other Mongol khanates, and was predominant in some places.
Comparison with the OTL
The Church in the Heirs of Alexandria timeline does not refer to itself as Catholic. At least among the Hypatians, it employs "counseling" rather than (or possibly in addition to) confession, though "counseling" is still done under seal of confidentiality, and with at least formal anonymity.
There is no indication of any equivalent to the Protestant Reformation, or to the earlier Lollard or Hussite movements. It is not known if there was any equivalent of the East–West Schism of the 11th century, which led to the formation of the Eastern Orthodox Church.
- In his online author notes for 1636: Seas of Fortune, Cooper notes several reason why Christianity would have drifted in Japan, even when it could be taught and practiced openly.
- The Shadow of the Lion, ch. 7; "This Rough Magic", ch. 17. The Gaelic creed is only mentioned in passing, and nothing specific is said about its doctrines. One of the main characters is noted as adhering to it, but it is not otherwise relevant to the storyline.
- Much Fall of Blood, ch. 6; Burdens of the Dead, chs. 23 and 28. Nestorian Christianity is only mentioned in passing. No specifics are given, though it is mentioned that some Mongols had adopted it, so its extent is not known. Historically, Nestorius (c.386 – c.450) was a conteporary of Hypatia and Chrysostom. While his known theological teachings came after the POD for the the HoA timeline, it is plausible that he formulated similar ideas in both timelines.