In 337 BC Attalus niece Cleopatra married to king Philip II of Macedonia. In spring of 336 BC, Philip II appointed Attalus and Parmenion as commanders of the advance force that would invade Persian Empire in Asia Minor. After Philip II had been assassinated and Alexander had become king (October 336 BC), Attalus was murdered.
The elder Attalus was the son of a brother (also called Attalus) of both Philetaerus, the founder of the Attalid dynasty, and Eumenes, the father of Eumenes I, Philataerus' successor; he is mentioned, along with his uncles, as a benefactor of Delphi.
Attalus' mother, Antiochis, was probably related to the Seleucid royal family (perhaps being the granddaughter of Seleucus I Nicator) with her marriage to Attalus' father likely arranged by Philetaerus to solidify his power.
Attalus was now forced to return to Asia, for he had learned at Opus that, at the urging of Philip, Prusias I king of Bithynia, related to Philip by marriage, was moving against Pergamon.
The elder Attalus, was the son of a brother (also called Attalus) of Philetaerus, the founder of the Attalid dynasty, and Eumenes, the father of Eumenes I, Philetaerus' successor; he is mentioned, along with his uncles, as a benefactor of Delphi.
Attalus was the first to speak in the council, but during his address, he stopped talking and fell down, one side of his body having become paralyzed.
According to Livy, Attalus received the delegation warmly, "and conducted them to Pessinus in Phrygia" where he "handed over to them the sacred stone which the natives declared to be "the Mother of the Gods," and bade them carry it to Rome".