In 101 BC, he had his mother murdered, married his niece Berenice III, and appointed his new wife as co-regent.

An Egyptian uprising in 91 BC caused Ptolemy X to lose control of the south of the country.

[8] Her new husband was waging a war against his half-brother Antiochus VIII (r. 125–96 BC), who was married to Cleopatra IV's elder sister Tryphaena.

[9] Perhaps as a result of this, in 114–113 BC, Alexander proclaimed himself 'King of Cyprus', openly declaring his opposition to Ptolemy IX.

Pausanias claims that Cleopatra III wounded a number of her own eunuch servants and displayed them to the people as evidence that her son had attempted to have her assassinated, causing the Alexandrians to riot and expel Ptolemy IX from the city.

Cleopatra III had him brought to Alexandria and placed on the throne as her new co-regent in September 107 BC.

Because of the means by which he came to the throne, he was given the derisory nickname Pareisactus (Greek: παρείσακτος, pareísaktos, "smuggled in").

[14] He assumed the epithet that had previously been borne by his brother, Philometor Soter (Mother-loving Saviour) and took his brother's place in the dynastic cult, in which he and his mother were worshipped as the Theoi Philometores Soteres (Mother-loving Saviour Gods).

Forces loyal to Cleopatra III and Ptolemy X expelled him, but he mounted another invasion of Cyprus in 106 BC, which succeeded in conquering the island.

Justin claims that the territory had originally been left to Apion in Ptolemy VIII's will, but it is not clear whether this was true or a post facto invention.

This will left all his territories to Rome in the event that he died without heirs, a method which was often used by Hellenistic kings to prevent rivals from attempting to depose or assassinate them.

[16][17] In 103 BC, the new Hasmonean King of Judaea, Alexander Jannaeus, attacked Ptolemais Akko.

Ptolemy X invaded Phoenicia by sea and then marched inland to Damascus, while Cleopatra III besieged Ptolemais Akko.

Ptolemy IX spent the winter encamped at Gaza, before deciding to sail back to Cyprus in early 102 BC.

[17] During this conflict, Cleopatra III and Ptolemy X made an alliance with the Seleucid king Antiochus VIII Grypus.

The rebellion also meant that the Ptolemies lost contact with the Triacontaschoenus region (Lower Nubia).

[22] Strabo says that Ptolemy X was expelled because he melted down the golden sarcophagus of Alexander the Great and replaced it with one made out of glass.

Ptolemy X and Berenice gathered a naval force to recapture the kingdom, but were defeated in battle.

It seems that providing collateral for this loan involved producing a will, which left Egypt to the Roman Republic in the event of his death without an heir.