Strabo Geography 13.4.2

[2] He had two brothers, the elder of whom was Eumenes, the younger Attalus. Eumenes had a son of the same name, who succeeded to the rule of Pergamum, and was by this time sovereign of the places round about, so that he even joined battle with Antiochus the son of Seleucus near Sardeis and conquered him. He died after a reign of twenty-two years. ¹ Attalus, the son of Attalus and Antiochis, daughter of Achaeus, succeeded to the throne and was the first to be proclaimed king, after conquering the Galatians in a great battle. Attalus not only became a friend of the Romans but also fought on their side against Philip along with the fleet of the Rhodians. He died in old age, having reigned as king forty-three years; ² and he left four sons by Apollonis, a woman from Cyzicus, Eumenes, Attalus, Philetaerus, and Athenaeus. Now the two younger sons remained private citizens, but Eumenes, the elder of the other two, reigned as king. Eumenes fought on the side of the Romans against Antiochus the Great and against Perseus, and he received from the Romans all the country this side the Taurus that had been subject to Antiochus. But before that time the territory of Pergamum did not include many places that extended as far as the sea at the Elaïtic and Adramyttene Gulfs. He built up the city and planted Nicephorium with a grove, and the other elder brother, ³ from love of splendor, added sacred buildings and libraries and raised the settlement of Pergamum to what it now is. After a reign of forty-nine years ⁴ Eumenes left his empire to Attallus, his son by Stratonice, the daughter of Ariathres, king of the Cappadocians. He appointed his brother Attalus ⁵ as guardian both of his son, who was extremely young, and of the empire. After a reign of twenty-one years, ⁶ his brother died an old man, having won success in many undertakings; for example, he helped Demetrius, the son of Seleucus, to defeat in war Alexander, the son of Antiochus, and he fought on the side of the Romans against the Pseudo-Philip, and in an expedition against Thrace he defeated Diegylis the king of the Caeni, and he slew Prusias, having incited his son Nicomedes against him, and he left his empire, under a guardian, to Attalus. Attalus, surnamed Philometor, reigned five years, ⁷ died of disease, and left the Romans his heirs. The Romans proclaimed the country a province, calling it Asia, by the same name as the continent. The Caïcus flows past Pergamum, through the Caïcus Plain, as it is called, traversing land that is very fertile and about the best in Mysia.