This bust is apparently meant to depict Mithridates, also known as Mithradates the Great (Megas) and Eupator Dionysius, who was king of Pontus and Armenia Minorin northern Anatolia (now Turkey) from about 120–63 BC. Mithridates is remembered as one of the Roman Republic’s most formidable and successful enemies, who engaged three of the prominent generals from the late Roman Republic in the Mithridatic Wars: Lucius Cornelius Sulla, Lucius Licinius Lucullus and Gnaeus Pompey Magnus. He is often considered the greatest ruler of the Kingdom of Pontus. Surprisingly Mithridates was rarely represented in artworks, but in those busts which still survive he doesn't look anything like how this bust is made (see image below). In this bronze reproduction, cast (once again) by the illusive E. Gastecloux at The Academy of Fine Arts, St Petersburg, He is adorned with an ivy/grape crown and beard, perhaps an allegorical representation of him as the God Bacchus or a philosopher. If you have any further information about this bust please get in touch!