Ptolemy XIII Theos Philopator

Ptolemy XIII Theos Philopator (Greek: Πτολεμαῖος Θεός Φιλοπάτωρ, Ptolemaĩos Theós Philopátōr, lived 62 BC/61 BC–January 13, 47 BC?, reigned from 51 BC) was one of the last members of the Ptolemaic dynasty (305–30 BC) of Egypt.

Son of Pharaoh Ptolemy XII of Egypt (80–58 BC and 55–51 BC), he succeeded his father in the spring of 51 BC as co-ruler of Egypt by his marriage to his older sister Cleopatra VII of Egypt (69–30 BC). In October 50 BC, Ptolemy XIII was promoted to senior ruler along with her, although the eunuch Pothinus acted as regent for him.

In the spring of 48 BC, Ptolemy XIII and Pothinus attempted to depose Cleopatra VII due to her increasing status as Queen. Her face appeared on minted coins, for example, while Ptolemy XIII's name was omitted on official documents. Ptolemy intended to become main ruler, with Pothinus acting as the power behind the throne.

Ptolemy XIII and Pothinus managed to force Cleopatra to flee to Syria, but she soon organized her own army and a civil war began in Egypt. Soon their other sister started to claim the throne as Arsinoe IV of Egypt (r. 48-47 BC), further complicating the situation.

At this point, defeated Roman general Pompey the Great came to Egypt seeking refuge from his pursuing rival Julius Caesar. Initially, Ptolemy XIII pretended to have accepted his request, but on September 29, 48 BC, he had the general murdered in hopes of winning favor with Caesar when the victorious general arrived. Caesar did arrive he was presented with the head of his deceased rival and former ally, but reportedly, instead of being pleased, reacted with disgust and ordered that Pompey's body be located and given a proper Roman funeral. Cleopatra VII proved more successful in winning Caesar's favor and became his lover. Caesar arranged the execution of Pothinus and the official return to the throne of Cleopatra VII, though she had never officially abdicated her marriage to Ptolemy XIII.

Still determined to depose Cleopatra VII, Ptolemy XIII allied himself with Arsinoe IV. Jointly, they organized the factions of the army loyal to them against those loyal to Cleopatra VII and the relatively small part of his army that had accompanied Caesar to Egypt. The battle between the warring factions occurred in mid-December 48 BC inside Alexandria itself (Siege of Alexandria (47 BC)), which suffered serious damage, including (according to some sources) the burning of some of the buildings which comprised the Library of Alexandria.

Upon the arrival of Roman reinforcements, the Battle of the Nile (47 BC) ensued and resulted in a victory for Caesar and Cleopatra, forcing Ptolemy XIII to flee the city. Ptolemy XIII reportedly drowned on January 13, 47 BC while attempting to cross the Nile. Whether he was attempting to flee or was seeking negotiations remains uncertain from sources of the time. Cleopatra VII remained the unchallenged ruler of Egypt, although she named their younger brother Ptolemy XIV of Egypt (40 BC) her new co-ruler.

In the motion picture Cleopatra (1963), Ptolemy was played by Richard O'Sullivan.