From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Eupator . See Antiochus v.

International Standard Bible Encyclopedia [2]

ū´pa - tor ( Εὐπάτωρ , Eupátōr , "of noble father"): The name given to Antiochus V who had succeeded his father Antiochus Iv (Epiphanes), 164 bc, while still a child under the guardianship of Lysias (1 Macc 3:32; 6:17). In the absence of Philip, a friend and foster-brother of the child's father, whom on his deathbed he had appointed guardian for his son, Lysias continued his duty as guardian, set the king upon the throne and named him Eupator. Shortly after his accession he collected a large army and marched against Jerusalem, accompanied by Lysias, for the relief of a Syrian garrison that was hard pressed by Judas Maccabeus (1 Macc 6:19ff). Judas was repulsed at Bethzacharias and after a severe struggle Bethsura was captured (1 Macc 6:31-50). The Jewish force in the temple was hard pressed and indeed reduced to the last extremity (1 Macc 6:53), when Lysias, hearing that his rival Philip had returned from Persia and had made himself master of Antioch (Josephus, Ant , Xii , ix, 5 f), made a hasty peace and returned to meet Philip, whom he easily overpowered. In the following year (162 bc) Antiochus and Lysias were put to death by Demetrius Soter, son of Seleucus, in requital of wrongs inflicted upon himself by Antiochus Epiphanes (1 Macc 7:2-4; 2 Macc 14:1, 2; Josephus, Ant , Xii , x, 1).