The Byzantium Empire was founded by Constantine the Great in 324 who renamed the city to Constantinople. The city was officially proclaimed the capital of the Roman empire (Byzantine) in 330.
Constantine converted to Christianity in 312 and then transformed the Roman empire into Christianity. In 381, during the reign of Theodosius I, the official state religion of the Roman Empire became Christianity, turning Constantinople into a thriving religious centre.
The Byzantine style was quite distinctive with religious icons being quite popular along with a flat perspective and use of gold as a form of style.
The split in the church, caused by disagreement between Rome and Constantinople, lead to the growth of Orthodoxy Christianity in the region. One of the dividing factors was the use of icon, such as the images of Jesus Christ and Virgin Mary. For the Byzatinians, these were more than images. They possessed the Holy Power. The Imperial powers in Constantinopole saw this as a threat while the papacy in Rome tolerated the images. This eventually caused the rift and the two churches separated.
Among the most famous Byzantinians is Justianian I who built the Hagia Sofia.