At first subject to the Seleucid king Antiochus I and later to Antiochus II, Diodotus rebelled in about 250 and took the title of king. Little is known of his reign, but, according to some scholars, the Seleucid king Seleucus II (Seleucus II Callinicus), in order to secure Diodotus' friendship, married one of his sisters to him during a time (246) when the Seleucid Empire was in chaos. Diodotus was succeeded by his son, Diodotus II, and after his death was called by the cult-name Soter (Saviour).