I, an Orthodox Christian, coming from that region don't know about the Byzantine Empire?

Obviously you don't know anything. Only the lies you have been told all your life, called brainwashing. For starters you have no idea the first Christian state was not Catholic Rome, but a Gnostic one, Osroene, with its capital at Edessa in modern Turkey. The Gnostic teacher, Bardesanes was able to convert the king of Edessa, Abgar IX, who established Bardesanes' version of Christianity as the state religion, which ended when Edessa was conquered by the Roman Emperor Caracalla in 216. Bardesanes also known as Bar-Daisan, was a Gnostic Christian writer and poet. He was born in the Syrian city-state of Edessa (now called Urfa, or Sanliurfa, in southern Turkey), where he later became a missionary after his conversion in 179. He was credited by church fathers with inventing the Christian hymn and wrote 150 songs that were popular for generations. The most famous is the “Hymn of the Pearl”.

What happened next, Christianity began to spread carried by devoted followers who risked their lives to share their faith. The message of Jesus resonated with many offering hope and redemption in a time of great turmoil. Over time the movement grew stronger eventually gaining the attention of the Roman Empire. By the early 4th Century emperor Constantine embraced Christianity leading to its widespread acceptance and the eventual establishment of the church as a dominant religious force. As Christianity evolved different interpretations of its core messages emerged giving rise to diverse and often conflicting beliefs.

I, an Orthodox Christian, coming from that region don't know about the Byzantine Empire?

Obviously you don't know anything. Only the lies you have been told all your life, called brainwashing. For starters you have no idea the first Christian state was not Catholic Rome, but a Gnostic one, Osroene, with its capital at Edessa in modern Turkey. The Gnostic teacher, Bardesanes was able to convert the king of Edessa, Abgar IX, who established Bardesanes' version of Christianity as the state religion, which ended when Edessa was conquered by the Roman Emperor Caracalla in 216. Bardesanes also known as Bar-Daisan, was a Gnostic Christian writer and poet. He was born in the Syrian city-state of Edessa (now called Urfa, or Sanliurfa, in southern Turkey), where he later became a missionary after his conversion in 179. He was credited by church fathers with inventing the Christian hymn and wrote 150 songs that were popular for generations. The most famous is the “Hymn of the Pearl”.

What happened next, Christianity began to spread carried by devoted followers who risked their lives to share their faith the message of Jesus resonated with many offering hope and redemption in a time of great turmoil over time the movement grew stronger eventually gaining the attention of the Roman Empire by the early 4th Century emperor Constantine embraced Christianity leading to its widespread acceptance and the eventual establishment of the church as a dominant religious force as Christianity evolved different interpretations of its core messages emerged giving rise to diverse and often conflicting beliefs.