A term from Roman antiquity for a subterranean sepulcher with wall niches or pigeonholes for cinerary urns. The term was also used for the recesses themselves. This type of burial was typically afforded to the large staff of slaves and freedmen. . Originating as variants of traditional Etruscan and republican Roman house tombs, columbaria were usually rectangular brick structures built around an open court, the walls of which contained niches for the urns. Some columbaria were elaborate and held numerous inscriptions, stucco paintings, and mosaics which provide information about the lower classes. Some of the best examples of columbaria are those in the great necropolis beneath the Basilica of San Sebastiano in Rome. In Hadrian's time (117-138 AD) inhumation replaced cremation and columbaria became obsolete.