Answer
Antiochus VII, the ruler of the Seleucid Empire, sought refuge in Alexander II's court after being dethroned by the usurper Tryphon. To ensure Antiochus' loyalty, Alexander II formally adopted him as his own son. This strategic move helped Alexander II maintain diplomatic relations with the Seleucids and solidified Antiochus' legitimacy as the next heir to the Seleucid throne.