There are three main branches of Christianity. In no particular order, they are:
- Orthodox Christianity
- Catholic Christianity
- Protestant Christianity
Orthodox Christianity: This includes two main branches, Eastern Orthodoxy, and Oriental Orthodoxy. Oriental Orthodoxy split from the rest of Christianity in the 5th century because they believed Christ had one complex nature instead of two natures (fully God and fully man) in one person.
Some churches that belong to Oriental Orthodoxy:
- The Armenian Apostolic Church
- The Coptic Orthodox Church
- The Ethiopian Orthodox Church
- The Syriac Orthodox Church
Eastern Orthodoxy split from Catholicism in the 11th century over political matters and doctrine matters such as the role of the Holy Spirit in the Trinity and church practices.
Some churches that belong to the Eastern Orthodox Church:
- The Greek Orthodox Church
- The Russian Orthodox Church
- The Romanian Orthodox Church
- The Orthodox Church in America
- The Ukrainian Orthodox Church
- The Latvian Orthodox Church
Catholic Christianity: Catholic Christianity split with the Eastern Orthodox in the 11th century and became the powerhouse of Europe for centuries. Today the Catholic Church is the largest religious sect in the world and in human history. This church includes members of the Roman Catholic Church as well as churches in full communion with Rome that are considered to be fully Catholic churches with no difference in doctrine but differences in tradition.
Some churches within the Catholic Church include:
- The Roman Catholic Church (by far the largest church and mother church of the Catholic Church)
- The Maronite Catholic Church
- The Russian Greek Catholic Church
- The Greek Byzantine Catholic Church
Other churches have split from the Catholic Church while maintaining Catholic ceremony, priesthood, and dogma. These are still considered Catholic churches, though they are not in communion with Rome.
Some churches that are not part of the Catholic Church, but still considered to be Catholic churches:
- The Polish Catholic Church
- The American Catholic Church
- The various Old Catholic churches
- The Liberal Catholic Church
Protestant Christianity: Protestants are members of churches that sought to reform the Catholic Church in the 16th century and onward. Most Christian denominations in the US are Protestant and it is a wide umbrella of churches. Basically, to be Protestant you must be a Christian church that split from the Catholic Church or a church that split off from the Catholic Church, believe in the Trinity, and accept the Bible as the Word of God and sole authority on matters of faith. The name itself reflects their origins, Protestant = one who protests the Catholic faith.
Some churches considered to be Protestant:
- Lutheran churches
- Anglican churches (Church of England, Episcopal Church USA, etc.)
- Presbyterian churches
- Methodist churches
- Congregationalist churches
- Most non-denominational churches
- Baptist churches
- The Moravian Church
- The Amish
- Mennonite churches
- Most Pentecostal churches
In addition to all of this, in the Protestant churches, there are a few other terms that are thrown around that need to be explained, as it can be very confusing. A lot of churches may fall into two or more of the following definitions, so it's possible for a church or a person to be one or many of these things.
Mainline Christianity: The historical churches of the Protestant Reformation and their immediate child churches. These include: Lutherans, Anglicans, Presbyterians, Congregationalists, Methodists, which were the majority churches in the United States up until the later portion of the 20th century.
Evangelical Christianity: Christians who accept Christ as their personal Lord and Savior, believe exclusively in the Bible as the only authority in matters of faith, believe they have a personal relationship with Jesus, and believe they have been born again in the Spirit after praying to God to save them.
Fundamentalist Christianity: Christians who believe that the Bible is the inspired Word of God without error in its original forms and the only guide in life. They believe in taking a literal approach to reading scripture, meaning they believe that anything that does not clearly say it's a metaphor is literally true word for word.
Progressive Christianity: Christians who believe that the Bible is an inspired text and the Word of God, but must be interpreted critically and with modern historical eyes. Often take much of the Bible metaphorically and with belief that these were ancient people living in a different time who wrote the book and we must look at how they saw the world to understand what the texts mean. Often very inclusive and involved with outreach to other churches and other religions.
Charismatic Christianity: Christians who believe they are washed in the Holy Spirit and given spiritual gifts from it. The most familiar gift is speaking in tongues (essentially incoherent babbling done in a trance), but other gifts include prophecy, faith healing, etc.
Additionally, there are 2 major worship styles in Christianity. These terms originate with Anglican churches as there is a wide spectrum of ceremonial practice in those churches, but I feel the terms are relevant to Christian worship in general. The styles are:
- Liturgical, or High Church worship.
- Low Church worship.
Liturgical or High Church worship: Characterized by highly structured ritual complete with special vestments that are to be worn by clergy, worship centered around an altar, chanting or traditional music, and possibly incense or bells.
Some churches with High Church worship are:
- All Eastern Orthodox churches
- All Oriental Orthodox churches
- All Catholic churches
- Many Anglican churches
- Many Lutheran churches
Low Church worship: Characterized by an informal church service. It can take on many forms including traditional or contemporary hymns, extremely simple vestments or street clothes worn by clergy, worship is centered around reading from the Bible and a sermon. Things like incense, bells, candles, etc are generally frowned upon.
Examples of churches with Low Church worship:
- All Baptist churches
- All Pentecostal churches
- Most Evangelical churches
- Most Presbyterian churches
- Some Lutheran churches
- Some Anglican churches
- Some Methodist churches
Some churches fall somewhere between these two styles, and that worship is called Broad Church worship.
While there are other Christian groups outside of these, these are what are historically considered to be Christianity. Other groups do believe that Jesus was the messiah, but are considered outside the historical creeds of Christianity for several reasons. These groups usually object to not being considered Christian and do consider themselves to be Christians, sometimes consider themselves to be the only true Christians.
Some groups generally considered to be outside of Christianity but consider themselves to be Christians:
- Oneness Pentecostals, as they deny the doctrine of the Trinity.
- Jehovah's Witnesses, as they deny the Trinity and divinity of Jesus.
- Church of Jesus Christ of Latter-day Saints (Mormons), as they deny the Trinity, believe in multiple gods, and have additional scriptures to the Bible.