Antiochus VI Dionysus in Wikipedia

Antiochus VI Dionysus (ca. 148–138 BC), king of the Hellenistic Seleucid kingdom, was the son of Alexander Balas and Cleopatra Thea, daughter of Ptolemy VI of Egypt. Antiochus VI did not actually rule. He was nominated in 145 BC by the general Diodotus Tryphon as heir to the throne in opposition to Demetrius II, and remained the general's tool. In 142 BC, Diodotus deposed and succeeded him and in 138 BC announced that he had contracted an internal disease and supposedly required surgery, which was presumably used to cover his murder at his supposed benefactor's bequest.