Relief sculpture refers to sculpture which projects from a two-dimensional background. There are two types: alto-relievo or high relief, and bas-relief or low relief. High relief sculpture is almost three dimensional, while bas-relief designs are barely more prominent than the surface of the background. Both types of relief sculpture have histories dating back over 20,000 years in Eastern and Western cultures. Two nice examples of relief sculpture are the Parthenon Frieze for the Athenian Akropolis (443–438 b.c.) and Lorenzo Ghiberti’s Gates of Paradise (1426–52) for the Baptistery of San Giovanni in Florence.

Cavalry from the Parthenon Frieze, British Museum

Details from Gates of Paradise, Lorenzo Ghiberti

(Images via Wikipedia, bluffton.edu)