Tough art and microbial drama

Abstract

Glass, ceramic, marble or limestone, shells, pebbles, enamel, ivory, mother-of-pearl, gold, painted and semiprecious stones-in the most refi ned form especially cut into hard cubes known as tesserae-were set at different angles and depths and arranged into tactile patterns depicting mythologic subjects, everyday or theatrical scenes, and many other themes to adorn architectural structures. Even though they were sometimes found outside buildings, mosaics were primarily used on interior surfaces. As the practice became more common, tesserae of colored glass were expressly produced to provide intense blue, red, and green hues, "Like very rubies from gold patinas gleaming," as Dante Alighieri would write in the Divine Comedy when he viewed the ancient mosaics in Ravenna, Italy.