Successor of: Philetaerus
- Father: Eumenes, brother of Philetaerus
- Mother: Satyra
- Adopted by Philetaerus.
- 263: Succeeds Philetaerus as lord of Pergamon and the valley of the Caicus; he behaves too independent in view of the Seleucid king Antiochus I Soter, who declares war.
- 261: Antiochus defeated.
- Eumenes remains friendly to Antiochus' successor Antiochus II Theos, although he is an ally of Ptolemy II Philadelphus of Egypt in the Second Syrian War; and he pays tribute to the Galatians.
- He adopts Attalus.
- 241: Death. Games are instituted in his honor, the Eumenia.
Succeeded by: Attalus I Soter