Ptolemy IX Lathyros in Wikipedia
Ptolemy IX Soter II or Lathyros ("grass pea") (Greek: Πτολεμαῖος Σωτήρ Λάθυρος, Ptolemaĩos Sōtḗr Láthuros) was king of Egypt three times, from 116 BC to 110 BC, 109 BC to 107 BC and 88 BC to 81 BC, with intervening periods ruled by his brother, Ptolemy X Alexander.
At first he was chosen by his mother Cleopatra III to be her co-regent (his father Ptolemy VIII wished that she would rule with one of her sons), though she was more forced to choose him by the Alexandrians. He married his sister Cleopatra IV, but his mother pushed her out and replaced her with his younger sister Cleopatra Selene. Later, she claimed that he tried to kill her, and successfully deposed him, putting her favorite son Alexander on the throne as co-regent with her. However, she later grew tired of the now Ptolemy X and deposed him, putting Ptolemy IX back on the throne. She was soon murdered by Ptolemy X, who took the throne again. He was then killed in battle, and Ptolemy IX reigned until his own death. In Alexandria, Ptolemy IX, replaced the sarcophagus of Alexander the Great with a glass one, and melted the original down in order to strike emergency gold issues of his coinage. The citizens of Alexandria were outraged at this and soon after, Ptolemy IX was killed.
His daughter Berenice III took the throne after his death, and reigned for about a year. She was forced to marry her stepson Alexander, who reigned under the name Ptolemy XI Alexander II and had her killed nineteen days later.
Ptolemy IX's name recalls that of his great Macedonian ancestor, Ptolemy I Soter; note that in older references and in younger ones by the German historian Huss, he may be numbered VIII.