HARPOCRATES, originally an Egyptian deity, adopted by the Greeks, and worshipped in later times both by Greeks and Romans. In Egypt, Harpa-khruti, Horus the child, was one of the forms of Horus, the sun-god, the child of Osiris. He was supposed to carry on war against the powers of darkness, and hence Herodotus (ii. 144) considers him the same as the Greek Apollo. He was represented in statues with his finger on his mouth, a symbol of childhood. The Greeks and Romans, not understanding the meaning of this attitude, made him the god of silence (Ovid, Metam. ix. 691), and as such he became a favourite deity with the later mystic schools of philosophy.
See articles by G. Lafaye in Daremberg and Saglio’s Dictionnaire des antiquités, and by E. Meyer (s.v. “Horos”) in Roscher’s Lexikon der Mythologie.