Classical sculpture refers loosely to the forms of sculpture from Ancient Greece and Ancient Rome, as well as the Hellenized and Romanized civilizations under their rule or influence from about 500 BC to around 200 AD. More precisely it refers to Ancient Greek sculpture from around 500 BC to the onset of the Hellenistic style around 323 BC. It may also refer stylistically to later sculpture done in a Neoclassical or classical style. Classical sculptures have been popular since the Renaissance. Only those works that closely follow the canon of classical forms would fall under the term.
In addition to free standing statues, the term classical sculpture incorporates relief work (such as the famous Elgin Marbles of the Parthenon) and the flatter bas-relief style. Whereas sculptural works emphasized the human form, reliefs were employed to create elaborate decorative scenes. ~Wikipedia