Ptolemy X Alexander I (, Ptolemaĩos Aléxandros) was King of Egypt from 107 BC till his death in 88 BC, in co-regency with his mother Cleopatra III as Ptolemy Philometor Soter until 101 BC, and then with his niece and wife Berenice III as Ptolemy Philadelphus. He was a son of Ptolemy VIII and Cleopatra III, and younger brother of Ptolemy IX. His birth name was probably Alexander. Ptolemy X was the second son of Ptolemy VIII and Cleopatra III, and his birth name was probably Alexander. When Ptolemy VIII died in 116 BC, Ptolemy IX became king with Cleopatra III as his co-regent and Alexander was sent to Cyprus to serve as governor. However, in 114–13 BC, he declared himself king. Cleopatra III quarrelled with Ptolemy IX and arranged for Alexander to return to Egypt in 107 BC and replace his brother as co-regent (with modern sources calling him Ptolemy X). During his reign, Ptolemy X had to fight against his brother Ptolemy IX to maintain control over the Egyptian throne. Cleopatra III and Ptolemy X fought a war against Ptolemy IX in the Hasmonean kingdom (103–102 BC), in which Ptolemy X successfully prevented his brother from invading Egypt. 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. In 88 BC, the people expelled him from Alexandria, recalling Ptolemy IX to the throne. Ptolemy X raised an army with Roman help and invaded Cyprus, but was killed. Background and early life Ptolemy X, born Alexander, was a member of the Greek Ptolemaic dynasty of Egypt. When King Ptolemy V had died in 180 BC, he had left three children: Ptolemy VI, Cleopatra II, and Ptolemy VIII. All three ruled together from 169 BC until 164 BC, when Ptolemy VIII expelled his brother from power. In 163 BC, he was expelled in turn and forced to withdraw to Cyrene. However, when Ptolemy VI died in 145 BC, Ptolemy VIII was invited back to Egypt to serve as king, marrying his sister Cleopatra II (who had previously been married to Ptolemy VI). The relationship between Ptolemy VIII and Cleopatra II rapidly deteriorated, especially when Ptolemy VIII took Cleopatra III, the daughter of Ptolemy VI and Cleopatra II), as a second wife. The