Explanation:
Seleucid Empire
The pretender to the Seleucid throne, Alexander Balas, who claims to be the son of the late Antiochus IV, defeats the Seleucid king, Demetrius I Soter, in battle and kills him. ... The new king of the Seleucid Empire, Alexander Balas, marries Cleopatra Thea, a daughter of Ptolemy VI Philometor of Egypt.