"Antiochus IX Eusebes Cyzicenus (Greek: Ἀντίοχος Εὐσεβής Κυζικηνός, "Antiochus the Pious, the Cyzicene") was a ruler of the Hellenistic Seleucid kingdom. He was the son of Antiochus VII Sidetes and Cleopatra Thea. He left the kingdom in 129 BC and went to the city of Cyzicus, but he returned in 116 BC to challenge his half-brother Antiochus VIII for power.
The siblings fought a twenty-year civil war. In 112 BC, Antiochus IX´s wife, Cleopatra IV, was killed by her sister Tryphaena, the wife of Antiochus VIII. Tryphaena herself died shortly afterwards. Antiochus VIII was assassinated in 96 BC; he was succeeded by his sons Seleucus VI and Demetrius III. Antiochus IX then took the capital Antioch and married his deceased wife´s sister Cleopatra Selene, who was herself the widow of Antiochus VIII. Seleucus VI continued the war against his uncle. Antiochus IX Eusebes Cyzicenus was killed in battle in 96 BC." - (en.wikipedia.org 31.01.2020)
en