Diodotus Tryphon was king of the Seleucid kingdom of Syria. As a general of the army, he promoted the claims of Antiochus VI Dionysus,the infant son of Alexander Balas, but then in 142 deposed the child and himself seized power in Palestine where Demetrius II was unpopular for his oppressive treatment of the Jews. Antiochus VI was kept alive in captivity until 138 BC. However, internal strife led in 143 BC to the establishment of Hasmonean rule, and in 138 Diodotus was attacked and defeated in Antioch by Antiochus VII of Side. Diodotus committed suicide.