A better term than factions might be sects[yes, sects not sex]. For example, Catholicism is a Christian sect. Methodists are a Christian sect. Baptists are a Christian sect, etc.. There are many, many different Christian sects. Too many to provide a comprehensive list of differences. What all Christian sects believe is that Jesus Christ is the savior of the world. From there, the sects vary wildly.
One of the most basic divisions would be Catholicism vs. Protestant. Catholics claim to be the original orthodox Christian church. They trace their authority through Christ, to Paul the Apostle, to the popes. MANY churches were started by religious reformers who protested against the Catholic church, claiming the Catholic church had become corrupted and no longer represented the true Christian faith. In some cases, churches were just rebelling against papal authority. Faiths founded by people protesting Catholicism are known as Protestant religions. Martin Luther is probably one of the foremost protestant reformers and the Lutheran church is based on his reformations. Other protestant faiths include the Methodists, the Anglicans, the Baptists, and the Episcopal.
Episcopal churches are interesting. On the surface, they appear catholic, with often times dark churches, intense imagery, ect. Behind the scenes, they are very progressive. A lot of women in power positions. Gay pride flags often outside their door or on the marquee. They take a very liberal stance on human issues, while keeping up on the classic beauty and almost 'performance art' that is appealing about the Catholic Church. And everyone seems happy on Sunday services. It's like happy catholic.
Another basic way to divide the sects is by where they claim to get their authority. The Catholics, Coptics, and Greek Orthodox are some of the oldest Christian denominations (another word for sects) and trace their priesthood authority back to Paul. A lot of other churches like the Baptists and the Pentecostals don't trace their authority back to ancient times. They often cite the Bible as their priestly authority or personal spiritual experiences. Mormons teach that priesthood authority was lost anciently and restored to a living prophet in modern times and trace their authority through that prophet to Christ, personally. Today, many protestant clergy get their ordinations (that's like their license to be a priest) by graduating from a divinity or theological school. Some Christian churches have paid clergy, others have an unpaid- laity- clergy.
Yet another way to classify Christian denominations is according to doctrine. One of the basic dividing doctrines is how a sect interprets the doctrine of The Trinity. Some churches believe that Christ, God the Father, and the Holy Ghost are one in the same being. Others see the three as manifestations of the same power. Still others see the three as distinct, separate beings that are one in purpose, attribute, and power.
Over all, it is estimated that there are over 40,000 Christian denominations across the world with over 2.2 billion members. I just moved to Georgia and it seems like there's about two different Christian churches on on every street!
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