Ptolemy XV Caesar, nicknamed Caesarion (little Caesar) (lived June 23, 47 to August, 30 BC; reigned September 2, 44 BC to August, 30 BC) was the son of Julius Caesar and Cleopatra VII of Egypt and the last pharaoh of the Ptolemaic dynasty of Egypt.

He was nominated co-ruler by his mother on September 2, 44 BC at the age of three. Although he was probably king in name only, with Cleopatra keeping actual authority to herself, he was intended by her to be the successor of his father. When Gaius Julius Caesar Octavianus (Octavian, later Augustus Caesar) invaded Egypt in 30 BC, Cleopatra tried to send Caesarion to India for safety, but the Romans intercepted and captured him. Octavian captured the city of Alexandria on August 1, 30 BC – the date that marks the official annexation of Egypt to the Roman Republic. Cleopatra's consort Mark Antony had committed suicide prior to Octavian's entry into the capital; she followed his example by committing suicide on August 12, 30 BC.

Octavian now had to deal with the fate of the captured child pharaoh. Octavian was a grand-nephew and adoptive son of Caesarion's father, but he feared that "too many Caesars", as he put it, would threaten his claim to being his adoptive father's sole successor: he decided that his adoptive brother must be put to death. Octavian then assumed control of Egypt. The year 30 BC was considered the first year of the new ruler's reign according to the traditional chronological system of Egypt. In lists of the time Octavian himself appears as a pharaoh and the successor to Caesarion.

Caesarion is the subject of a poem written in 1918 by Konstantinos Petrou Kavafis.
Kilde: http://en.wikipedia.org/wiki/Caesarion