system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Whats the difference between Christianity and Orthodox Christianity?
gpt
The meaning of "Orthodox" in the Christian teaching is to denote a kind of Christianity that, according to the speaker, is close to the early Christian beliefs. This means that many different branches of Christianity are likely to regard themselves as orthodox, even if they are at odds with each other regarding theological matters.

"Orthodox Christianity" is often used to refer to the Eastern Orthodox Church, which is one of the branches of Christianity, one that is mainly practiced in Eastern Europe, Greece and Russia. In this sense of "Orthodox", the question about the difference between Christianity and Orthodox Christianity is similar to asking "what's the difference between a sandwich and a ham sandwich?". Eastern Orthodox Christianity is one of the branches of Christianity.

Basically, like the Roman Catholic church, it believes it is the kind of Christianity that carries on the original intent and authority of Christ and His apostles. Unlike the Roman Catholic church, it is not united under the authority of a single pope, but rather it is a group of related churches with their own religious leaders. The Roman Catholic Church and the Eastern Orthodox Church (which also calls itself the Catholic Church) were joined together in most matters until 1054, when they split due to disagreements. One of those was the issue of the authority of the Pope.