King of Pontos, in modern-day Turkey. See http://en.wikipedia.org/wiki/List_of_Kings_of_Pontus and http://en.wikipedia.org/wiki/Mithridates_III_of_Pontus

Assumed to be the son of Mithradates II.

Mithridates III of Pontus

Mithridates III (Greek: Mιθριδάτης) was the fourth King of Pontus, son of Mithridates II of Pontus and Laodice. Mithridates had two sisters who were Laodice III the first wife of the Seleucid King Antiochus III the Great and Laodice of Pontus. He may have ruled in an uncertain period between 220 BC and 183 BC. Nothing is known of him since the years just cited, because the kingdom of Pontus disappears from history. His same existence is contested by certain historians, even if it is necessary to account for Appian's indication of Mithridates VI of Pontus as the eighth king of the dynasty and the sixth of the name. Mithridates married an obscure Seleucid Princess called Laodice. By his wife, he had three children: Mithridates IV of Pontus, Pharnaces I of Pontus and Laodice.

Source :

https://en.wikipedia.org/wiki/Mithridates_III_of_Pontus