Cleopatra

Cleopatra VII was queen of Egypt and the wife of Mark Antony. (PROSE: State of Change, The Last Pharaoh) She was Greek, although it was a common mistake to think she was Egyptian. (PROSE: The Lonely Computer)

The Fifth Doctor reported to have met Cleopatra at some point. He described her as having "the succour and grace of a carpet flea." (AUDIO: Loups-Garoux)

Cleopatra was abducted by Momus while she had Mark Antony waiting in her studio. Donna Noble and the Tenth Doctor encountered her among several other historical figures from Earth who were also abducted by Momus. (PROSE: The Lonely Computer)

The Sixth Doctor and Peri Brown watched Cleopatra's barge on the River Nile in preparation for the Battle of Actium. (PROSE: State of Change)

Within a year of the Battle of Actium, Cleopatra committed suicide. (PROSE: The Last Pharaoh)

Alternate timelines
On the duplicate Earth known as Terra Nova, Cleopatra and Mark Antony won the Battle of Actium and had three children. (PROSE: State of Change)

In an alternate timeline in which all of history happened at the same moment because River Song refused to kill the Eleventh Doctor, Cleopatra met with Holy Roman Emperor Winston Churchill in Gaul. River Song also got her to give Amy Pond the Great Pyramid of Giza by using hallucinogenic lipstick and a gun. (TV: The Wedding of River Song)

Behind the scenes

 * According to The Brilliant Book 2012, a book that contains non-narrative based information, the alternate Cleopatra was on Facebook. She was friends with River, Churchill and Napoleon Bonaparte. She was a fan of Vincent van Gogh and Silurian medicine and played live chess with Joseph Stalin; she also read the book Murder on the Sky Orient Express and joined the online groups Can I get 6,000,000,000 people to join this group before 5.03pm??? and I'm not being funny but I think this is all the Doctor's fault!
 * She was portrayed by Claire Bloom in the 1956 version of Caesar and Cleopatra.