The structure and appearance of Byzantine churches evolved significantly during the thousand year history of that empire. Early churches were based closely on patterns drawn from Roman civic and religious architecture. Churches constructed during the middle years of the Byzantine Empire tended to follow a unique architectural plan featuring large and richly-decorated domes. Byzantine churches erected during the waning years of the empire were often less richly-decorated, and began to feature a wall of icons.
The first Byzantine churches were built on a Roman model, as the Byzantine Empire was the Eastern Roman Empire. These churches typically featured a basilica layout. This type of floor plan features twin rows of columns that partially separate aisles along the side of a rectangular structure, and also serve to support the roof. A curved apse is usually located at the end of the basilica. Wings were sometimes added to this structure, creating a cruciform shape, but were generally shorter than the main hall of the basilica.
As the culture of the Byzantine Empire became more thoroughly Greek, a new style of Byzantine church emerged. The Hagia Sophia, perhaps the most famous Byzantine building of all, showcases the key features of this style. In this church, there is a central dome, and four wings of equal length lead off from that dome. This is a substantial departure from a traditional basilica plan and was made possible by architectural advances that made the construction of larger domes possible.
Religious art in Byzantine churches typically employed rich materials to decorate most visible surfaces. Churches in wealthy regions would be covered entirely in mosaics, an art at which the Byzantines excelled. Glass shards and gold leaf were used together to create vivid colors and to enhance the impact of the light that was allowed into Byzantine churches by improved dome construction. Marble and other expensive materials were used to make churches more beautiful, and although some churches featured religious frescos, mosaics were preferred.
Artwork in Byzantine churches usually depicted stylized religious figures. These figures were meant to convey a symbolic and spiritual message, rather than to precisely depict the human form. Early churches, such as San Vitale in Ravenna, did sometimes depict recognizable human figures, but this became much less common in later years. The depiction of the human form, even for religious reasons, was controversial in the Byzantine church, and a period of iconoclasm began in the 700s, during which much church art was destroyed. Churches erected during this period were typically not ornamented with images of human beings, even stylized ones.
In the waning years of the Empire, icons were once more embraced. Byzantine churches built in the last centuries of the Byzantine Empire not only featured religious images on their walls but added a wall of icons at the front of the church. This wall came to be entirely covered in Byzantine icons, painted in the stylized manner that had developed centuries earlier. Church decoration during this period was generally less lavish, as the Empire’s fortunes were fading.