He succeeded Attalus II, although their relationship, if any, is unknown. Attalus III had little interest in ruling Pergamum, devoting his time to studying medicine, botany, gardening, and other pursuits. He had no children or heirs of his own, and in his will he left the kingdom to the Roman Republic. Tiberius Gracchus requested that the treasury of Pergamum be opened up to the Roman public, but the Senate refused this.
Not everyone in Pergamum accepted Rome's rule. Aristonicus, who claimed to be Attalus' brother as well as the son of Eumenes II, an earlier king, led a revolt among the lower classes. The revolt was put down in 129 BC, and Pergamum was divided among Rome, Pontus, and Cappadocia.
Eumenes I, Attalos I and Eumenes II were enthroned successively after Philetarios.
Eumenes II took acropolis of Athens as an example and had the acropolis of Pergamon adorned with works of art which reflected fine taste, and Pergamon became one of the most graceful cities of the world.
AttalosIII who succeeded Attalos II, handed over his land to the Romans when he died in 133 B.C. In the Acropolis, the remains that you see on the left hand side while going in, are the monumental tombs or heroons built for the kings of Pergamon during the Hellenistic period.
Alexander III of Macedon (356 - 323 BC), the son of the brilliant ruler and strategist Philip II of Macedon, was born in Pella.
Darius III escaped once again but his army was shattered at the Battle of Gaugamela, the last big battle of the war which took place between Nineveh and Arbela on the 1st October 331 BC.
Antiochos III was defeated at the Battle of Magnesia (189 BC) and lost his lands beyond the Taurus range, to Rome.