Byzantine art is the artistic products of the Eastern Roman, or Byzantine, Empire, as well as the nations and states that inherited culturally from the empire. Though the empire itself emerged from Rome's decline and lasted until the Fall of Constantinople in 1453, many Eastern Orthodox states in Eastern Europe, as well as to some degree the Muslim states of the eastern Mediterranean, preserved many aspects of the empire's culture and art for centuries afterward.
A number of states contemporary with the Byzantine Empire were culturally influenced by it, without actually being part of it (the "Byzantine commonwealth"), such as Bulgaria, Serbia, and the Rus, as well as some non-Orthodox states the Republic of Venice and Kingdom of Sicily, which had close ties to the Byzantine Empire despite being in other respects part of western European culture. Art produced by Eastern Orthodox Christians living in the Ottoman Empire is often called "post-Byzantine." Certain artistic traditions that originated in the Byzantine Empire, particularly in regard to icon painting and church architecture, are maintained in Greece, Serbia, Bulgaria, Macedonia, Russia and other Eastern Orthodox countries to the present day.
Mosaic is the art of creating images with an assemblage of small pieces of colored glass, stone, or other materials. It may be a technique of decorative art, an aspect of interior decoration, or of cultural and spiritual significance as in a cathedral. Small pieces, mostly roughly square, of stone or glass of different colors, known as tesserae, (diminutive tessellae), are used to create a pattern or picture.