Cleopatra Selene I (Greek: Κλεοπάτρα Σελήνη; c. 135/130 – 69 BC) was the daughter of Ptolemy VIII Physcon by his niece Cleopatra III of Egypt. She was the wife of three different kings; including queen consort to Ptolemy IX Lathyros of Egypt, and later queen of Syria.
Originally she was named Selene, only adding the Ptolemaic throne name Cleopatra after her marriage with Lathyros. whom she married after his wife, her sister Cleopatra IV, was forced out by her mother. (115 BC). Selene was not, however, made co-ruler, unlike many of the sister-wives of Ptolemaic kings.
She bore Lathyros at least one daughter, Berenice III and two sons, including Ptolemy XII and possibly another son, also named Ptolemy.
In 107 BC, as relations deteriorated between Lathyros and his mother and co-ruler, Cleopatra III, he was forced to leave Egypt and his wife, first to Cyprus to raise an army, and then to south Syria from whence he tried, in 103 BC, to invade Egypt.
In the meantime, Cleopatra III established an alliance with one of the warring Syrian kings, Antiochus VIII Grypus, giving him Cleopatra Selene I as his wife. (His previous wife, (Cleopatra?) Tryphaena, Cleopatra Selene's I older sister, had been killed in 111 BC by his stepbrother Antiochus IX Cyzicenus).
In Syria, the civil war between Grypus and Cyzicenus over the throne in Antioch lasted until 96 BC, when Grypus was assassinated in Antioch. Cyzicenus, after capturing the capital, married Cleopatra Selene I. (Cyzicenus had been married to Cleopatra Selene's I older sister, Cleopatra IV, who had been killed by Grypus in 112 BC.)
Cyzicenus, however, was not to live much longer. Grypus had five sons with Cleopatra Tryphaena; all of them competing for the throne of Antioch. In 95 BC, Cyzicenus was killed during a battle with Seleucus VI Epiphanes, the eldest son of Grypus.