COSMATI WORK — a mosaic technique developed by Roman decorators and architects in the 12th and 13th centuries, named after the Cosmati family of marble workers. This unique style features right-angled, square, and triangular tesserae arranged in geometric patterns surrounding roundels of red porphyry and green serpentine.

Cosmati work involved the meticulous arrangement of colored stones, including red porphyry, green serpentine, marbles of various hues, and glass paste. These materials were combined with large stone disks and strips to create intricate geometric designs. The term "Cosmati" is derived from the name Cosma, which was associated with several families involved in this art form.

Distinguished from similar mosaic techniques of the time, Cosmati work emphasized a balance between intricate patterns and areas of plain stone, following the ancient Roman principles of clarity, simplicity, and monumentality. The production of Cosmati work faced a temporary hiatus in the 14th century when the papal seat was relocated to Avignon, France. Subsequently, the technique reemerged but in a diminished form.

Cosmati work adorned architectural surfaces and ecclesiastical furnishings, leaving a remarkable legacy in churches and cathedrals. Its designs exhibited a harmonious blend of intricate detail and understated elegance. The geometric precision and skillful craftsmanship of Cosmati mosaics have captivated art enthusiasts and continue to inspire contemporary artists today.

Although Cosmati work experienced a decline in popularity over time, its influence can be seen in subsequent mosaic traditions. The legacy of the Cosmati family and their mosaic technique remains an important part of the artistic and architectural heritage of the medieval period, reflecting a fusion of Roman craftsmanship and medieval ingenuity.