During the Byzantine era (4th to 15th century CE) mosaics became a popular artistic method of decorating religious buildings. During the Byzantine period, a wide variety of materials began to be used in including glass, gold and precious stones.
To create the tesserae (small pieces of material), a hammer and chisel-like blade (now called a hardie) were used to cut the material to the needed shape. Those tools are still used to this day by mosaic artists around the world.
The Byzantine Empire was a vast and powerful civilization with origins that can be traced to 330 A.D., when the Roman emperor Constantine I dedicated a “New Rome” on the site of the ancient Greek colony of Byzantium. Though the western half of the Roman Empire crumbled and fell in 476 A.D., the eastern half survived for 1,000 more years, spawning a rich tradition of art, literature and learning and serving as a military buffer between Europe and Asia. The Byzantine Empire finally fell in 1453, after an Ottoman army stormed Constantinople during the reign of Constantine XI.*
Constantiople and Ravenna
The Emperor Constantine’s conversion to Christianity lead to extensive building of Christian basilicas in the late 4th century CE, in which floor, wall, and ceiling mosaics were adopted for Christian uses. This was true in both the Capital Constantinople (now Istanbul) and Ravenna, Italy the “other” capital of Byzantium.