Antiochus VIII Epiphanes/Callinicus/Philometor, nicknamed Grypus, was the ruler of the Hellenistic Seleucid Empire from 125 to 96 BC. He was the younger son of Demetrius II and Cleopatra Thea. He may have spent his early life in Athens and returned to Syria after the deaths of his father and brother Seleucus V. At first he was joint ruler with his mother. Fearing her influence, Antiochus VIII had Cleopatra Thea poisoned in 121 BC.
Political instability affected most of Antiochus VIII's reign. From 116 BC he fought a civil war against his half-brother Antiochus IX. Antiochus VIII's wife, the Ptolemaic Egyptian princess Tryphaena, had her sister and the wife of Antiochus IX, the former Cleopatra IV of Egypt, murdered in 112 BC; Antiochus IX killed Tryphaena in revenge. In 102 BC, Antiochus VIII's aunt Cleopatra III of Egypt, the mother of the two rival queens, gave him the hand of her daughter Cleopatra Selene in marriage. Antiochus VIII was assassinated in 96 BC.