A mosaic is a picture or pattern made by placing, or fixing, small different-colored pieces of stone or glass side by side.
The art was an invention of the Mediterranean peoples and flowered between c. 300-31 B.C. In the Roman period, or about the first five hundred years of the Christian era, mosaics of great beauty ad variety were designed all over the empire spreading from Syria to Spain, and from Africa to Britain. The most brilliant mosaics in the world adorn walls and ceilings of sacred buildings in Rome, Ravenna and Salonika. Mosaics which have been discovered dating from the pre-Christian era were for the most part laid on the floor.