The Eastern Orthodox Church, officially the Orthodox Catholic Church, or simply the Orthodox Church, is a Christian church. Their type of Christianity is also called Orthodox Christianity or Orthodoxy. Their members are called Orthodox Christians, although there is another group of Churches called Oriental Orthodox that is not in communion with the Orthodox Church. There are about 300 million Orthodox Christians in the world. Most Orthodox Christians are found in Russia, Greece, Eastern Europe, and the Middle East, but there are Orthodox Christians everywhere around the world.
The Eastern Orthodox Church teaches that it is the Church started by Jesus Christ in his instructions to the Apostles. It practices what it understands to be the original Christian faith and maintains the sacredtradition passed down from the apostles.
In 395, the Roman Empire was split into a western part and an eastern part. The western part lasted to the 5th or 6th century. Τhe exact dates are a point of debate. The eastern part, which is commonly called Byzantine Empire, lasted until the 15th century. The split of the Roman Empire also affected the church, which developed differently in both parts. In 1054, there was the East–West Schism. The western part developed what is now the Roman-Catholic Church, and the eastern part is now called Eastern Orthodox Church. In the west, there is the Patriarch of Rome, who is commonly called the Pope. In the east, there is the Patriarch of Constantinople. Because of historical developments, many Eastern Orthodox churches also have a local Patriarch. In the west, the Pope is an absolute leader. The Patriarch of Constantinople is the "first among equals"; his power is not absolute, as seen when meeting with other Patriarchs. His power is the same of all bishops, which is what a patriarch is.
I believe in one God, the Father, the Almighty, Creator of heaven and earth and of all things visible and invisible.
And in one Lord Jesus Christ, the only begotten Son of God, begotten of the Father before all ages.
Light of Light, true God of true God, begotten not created, of one essence with the Father through whom all things were made.
For us and for our salvation he came down from heaven and was incarnate by the Holy Spirit and the Virgin Mary and became man.
He was crucified for us under Pontius Pilate, and he suffered and was buried.
On the third day he rose according to the Scriptures.
He ascended into heaven and is seated at the right hand of the Father.
He will come again in glory to judge the living and dead. His kingdom will have no end.
And in the Holy Spirit, the Lord, the Giver of life, who proceeds from the Father, who together with the Father and the Son is worshiped and glorified, who spoke through the prophets.
In One, Holy, Catholic, and Apostolic Church.
I acknowledge one baptism for the forgiveness of sins.
I expect the resurrection of the dead.
And the life of the ages to come. Amen.
In summary, they believe in one God. He has three parts, but they are one and the same (of one essence). As the Son (Jesus), he arrived from Heaven, died, and resurrected. He will eventually return as a judge for all humanity, as mentioned in the Bible.
Distribution of Eastern Orthodoxy in the world by country
The many churches of the Orthodox Church are distinct in terms of administration and local culture, but for the most part exist in full communion with one another. Most of these churches are led by patriarchs. Most patriarchs recognise the Patriarch of Constantinople as their spiritual leader.
The following listing contains a selection of Eastern Orthodox Churches. Unless otherwise stated, they are in communion:
In the 17th century a group of people split from the Eastern Orthodox Church because they did not agree with some changes that were introduced. These people are known as Old Believers today. There are two big groups of Old Believers and a few smaller ones. Old Believers are not in communion with the other Eastern Orthodox Churches.