Berenice II Euergetis was ruling queen of Cyrenaica from around 250 BC and queen and co-regent of Ptolemaic Egypt from 246 BC to 222 BC as the wife of Ptolemy III Euergetes.
She inherited the rule of Cyrene from her father, Magas in 249 BC. After a short power struggle with her mother, Berenice married her cousin Ptolemy III, the third ruler of the Ptolemaic kingdom. This marriage led to the re-incorporation of Cyrenaica into the Ptolemaic empire. As queen of Egypt, Berenice participated actively in government, was incorporated into the Ptolemaic state cult alongside her husband and worshipped as a goddess in her own right. She is best known for sacrificing her hair as a votive offering, which led to the constellation Coma Berenices being named after her. Berenice was murdered by the regent Sosibius shortly after the accession of her son Ptolemy IV Philopator in 221 BC.