Before its fall to the Ottoman Turks in 1453CE, the Byzantine empire had many other nations vying for their wealthy homeland such as the Persians, and also the Muslims. For an empire who relied on the walls that they so strongly pride in around their precious capital, the wall not only protected the citizens and its riches, it also protected the culture of the Byzantine Empire. That culture being.. the Orthodox Christianity - the one divided from Western Rome.
The split occurred in 1054CE during The Great Schism when Western Rome made Charlemangne as Emperor in 800CE, where the Byzantine viewed it as a pledge to disloyalty and a show of redundancy to their own Emperor.
So why then do people have such a bad impression of the Orthodox church? I do have to admit the word Orthodox can be quite daunting, and seems to have a negative connotation behind it.. (at least to me). But anyways, between the Orthodox and Catholics, they do have their similarities.
The Orthodox church share the foundation of Christianity of which the Heresies is also based on; a monotheistic belief in the trinity.
Neither do both of them worship Mother Mary or the saints either; a common misconception but others.
However, despite this core belief that they share, the Orthodox and Catholic Christianity were further divided thanks to their geography:
They were also divided by language; where the Byzantines know little Latin and spoke mainly Greek. It wasn't easy to the Patriarchs of Constantinople to communicate with other patriarchs of Antioch, Alexandria and Jerusalem.
If you still don't get how two Christian faith could be divided yet still worshipping the same God, take the Islamic faith for example. They have the Sunis and Shia Muslims are divided even though they both worship Allah. It is because of their divided views on the Prophet Mohammad that out of the Islamic faith birthed two divisions. This goes the same for the Roman Christianity. But you know what, this video would probably do you some good.