A contested paternity
Cleopatra named her son Ptolemy Caesar and maintained that Julius Caesar was his father. Roman writers preserve both the claim and contemporary doubts. Caesar did not adopt Caesarion; his testament instead adopted Octavian.
The last Ptolemaic king
Cleopatra associated Caesarion with her rule, and he became Ptolemy XV. After Alexandria fell, Octavian ordered the young king killed. His death ended the male Ptolemaic royal line and removed a potential rival bearing Caesar’s name.
Historical sources
Suetonius, Julius Caesar 52; Augustus 17
The disputed paternity and Caesarion’s death.
Plutarch, Life of Antony 54; 81
Caesarion at the Donations of Alexandria and after the conquest of Egypt.