<Tr> <Td_colspan="2"> The Pergamon Altar, Smarthistory </Td> </Tr> <P> After the death of Lysimachus, one of his officers, Philetaerus, took control of the city of Pergamum in 282 BC along with Lysimachus' war chest of 9,000 talents and declared himself loyal to Seleucus I while remaining de facto independent . His descendant, Attalus I, defeated the invading Galatians and proclaimed himself an independent king . Attalus I (241--197 BC), was a staunch ally of Rome against Philip V of Macedon during the first and second Macedonian Wars . For his support against the Seleucids in 190 BC, Eumenes II was rewarded with all the former Seleucid domains in Asia Minor . Eumenes II turned Pergamon into a centre of culture and science by establishing the library of Pergamum which was said to be second only to the library of Alexandria with 200,000 volumes according to Plutarch . It included a reading room and a collection of paintings . Eumenes II also constructed the Pergamum Altar with friezes depicting the Gigantomachy on the acropolis of the city . Pergamum was also a center of parchment (charta pergamena) production . The Attalids ruled Pergamon until Attalus III bequeathed the kingdom to the Roman Republic in 133 BC to avoid a likely succession crisis . </P> <P> The Celts who settled in Galatia came through Thrace under the leadership of Leotarios and Leonnorios c. 270 BC . They were defeated by Seleucus I in the' battle of the Elephants', but were still able to establish a Celtic territory in central Anatolia . The Galatians were well respected as warriors and were widely used as mercenaries in the armies of the successor states . They continued to attack neighboring kingdoms such as Bithynia and Pergamon, plundering and extracting tribute . This came to an end when they sided with the renegade Seleucid prince Antiochus Hierax who tried to defeat Attalus, the ruler of Pergamon (241--197 BC). Attalus severely defeated the Gauls, forcing them to confine themselves to Galatia . The theme of the Dying Gaul (a famous statue displayed in Pergamon) remained a favorite in Hellenistic art for a generation signifying the victory of the Greeks over a noble enemy . In the early 2nd century BC, the Galatians became allies of Antiochus the Great, the last Seleucid king trying to regain suzerainty over Asia Minor . In 189 BC, Rome sent Gnaeus Manlius Vulso on an expedition against the Galatians . Galatia was henceforth dominated by Rome through regional rulers from 189 BC onward . </P> <P> After their defeats by Pergamon and Rome the Galatians slowly became hellenized and they were called "Gallo - Graeci" by the historian Justin as well as Ἑλληνογαλάται (Hellēnogalátai) by Diodorus Siculus in his Bibliotheca historica v. 32.5, who wrote that they were "called Helleno - Galatians because of their connection with the Greeks ." </P>

Describe three changes in the arts and philosophy during the hellenistic age