The child Antiochus VI does not actually rule in Syria.

Either already in 145 or in early 144 BCE he had been nominated by the general Diodotus Tryphon as heir to the throne in opposition to Demetrius II, and remains the general's tool.

The young king dies in about 142/41 BCE.

While some ancient authors make Diodotus Tryphon responsible for the death of the king, others write that he died during a surgery.

Diodotus seizes power in Coele-Syria where the rival Seleucid king, Demetrius II Nicator, is unpopular for his oppressive treatment of the Jews. (Strictly speaking, Coele, or 'hollow', Syria, the region of southern Syria disputed between the Seleucid dynasty and the Ptolemaic dynasty, is the Beqaa Valley of Lebanon, but it is often used to cover the entire area south of the river Eleutherus including Judea.)

The division of the kingdom between the legitimate Seleucid heir and the usurper in Antioch persists.