After the Seleucid defeat at the Battle of Magnesia in 190 BC, the kings of Sophene and Greater Armenia revolted and declared their independence, with Artaxias becoming the first king of the Artaxiad dynasty of Armenia in 188. During the reign of the Artaxiads, Armenia went through a period of hellenization. Numismatic evidence shows Greek artistic styles and the use of the Greek language. Some coins describe the Armenian kings as "Philhellenes". During the reign of Tigranes the Great (95–55 BC), the kingdom of Armenia reached its greatest extent, containing many Greek cities including the entire Syrian tetrapolis. Cleopatra, the wife of Tigranes the Great, invited Greeks such as the rhetor Amphicrates and the historian Metrodorus of Scepsis to the Armenian court, and - according to Plutarch - when the Roman general Lucullus seized the Armenian capital Tigranocerta, he found a troupe of Greek actors who had arrived to perform plays for Tigranes. Tigranes' successor Artavasdes II even composed Greek tragedies himself.

Answer this question, if possible (if impossible, reply "unanswerable"): When did the Seleucid defeat the Battle of Magnesia?
190 BC