This is the equestrian sculpture of Marco Aurelio, a restored work from the empire times.
Among the most famous works you will find in the 'Musei Capitolini', are the "doves mosaic" --a wonderful work from the old Rome discovered in Tivoli-- and the "Capitoline Venus" --a Roman copy of an original Greek work. You will also find many other pictures and sculptures by Algardi, Caravaggio and Bernini.