The possibility of employing speckle interferometry for the non-destructive testing of the statue of Marco Aurelio has been evaluated. A simple and accurate speckle interferometer has been developed, using the relief image formed on the photographic emulsion as a reflecting phase grating. As a result, the displacement components parallel to the photographic emulsion plane have been measured within a range of 0.1-10mm for several points of the horse statue when it was loaded in the same position as the detached statue of the rider. -- AATA