In 261 BC, she married the Seleucid monarch Antiochus II Theos, who, following an agreement with Ptolemy (249 BC), had divorced his wife Laodice I and transferred the succession to Berenice's children.
In 246 BC, when Ptolemy died, Antiochus II took up again with his first wife, Laodice. The Syrian king died shortly thereafter, many suspect from poisoning. Queen Berenice claimed the regency for her infant son Antiochus and conquered Soloia with her army; however, she and her son were both killed by Laodice. Berenice's brother, Ptolemy III Euergetes, succeeded their father and set about to avenge his sister's murder by invading Syria and having Laodice killed. This is also mentioned in the Book of Daniel 11:6.