-- Who is depicted?

 Neptune was the god of freshwater and the sea in Roman religion. He is the counterpart of the Greek god Poseidon. In the Greek-influenced tradition, Neptune was the brother of Jupiter and Pluto; the brothers presided over the realms of Heaven, the earthly world, and the Underworld. Salacia was his consort.

Depictions of Neptune in Roman mosaics, especially those of North Africa, are influenced by Hellenistic conventions. Neptune was likely associated with fresh water springs before the sea. Like Poseidon, Neptune was worshipped by the Romans also as a god of horses, under the name Neptunus Equester, a patron of horse-racing.

-- More about the artist

 Gabriël Grupello (also Gabriël de Grupello or Gabriël Reppeli; 22 May 1644 – 20 June 1730) was a Flemish Baroque sculptor who produced religious and mythological sculptures, portraits and public sculptures. He was a virtuoso sculptor who enjoyed the patronage of several European rulers.