How many years did Cleopatra rule Egypt?

Cleopatra ruled Egypt for 21 years, from 51 BC until her death in 30 BC. She initially governed as co-ruler with her younger brother Ptolemy XIII, following the succession plan of their father, Ptolemy XII Auletes.

The reign was not a simple uninterrupted period of sole rule. Cleopatra was briefly driven from Alexandria during a power struggle with Ptolemy XIII, but she returned with the support of Julius Caesar after Caesar became involved in the Egyptian civil war. Following Ptolemy XIII's death in 47 BC, she ruled with another younger brother, Ptolemy XIV, and later with her son Caesarion.

Cleopatra's 21-year reign ended when Octavian defeated the forces of Cleopatra and Mark Antony. After Antony's death and Cleopatra's own suicide in Alexandria in 30 BC, Egypt became a Roman province. Her reign therefore marks both the final major phase of the Ptolemaic Kingdom and the end of independent Hellenistic rule in Egypt.