Seleucus V Philometor in Wikipedia

The Seleucid king Seleucus V Philometor (126 - 125 BC), ruler of the Hellenistic Seleucid kingdom, was the eldest son of Demetrius II Nicator and Cleopatra Thea.[1] The epithet Philometor means mother-loving and in the Hellenistic world usually indicated that the mother acted as co-regent for the prince. In 126 BC Demetrios II was murdered at the instigation of his wife Cleopatra Thea. Now she herself took power and soon also killed her oldest surviving son Seleucus V. Two different motives are given as reason for this deed: According to one version he had attempted to claim the throne without her agreement,[2] according to the other version she was afraid that he might avenge the assassination of his father.[3]