Empress Messalina (wife of Claudius) was infamous for her voracious sexual appetite. She would often sell herself on the street like a common whore, and, still unsatisfied after the brothels closed for the night, had to be thrown out.
Her most famous exploit was when she decided to hire a prostitute famous for her stamina and challenge her to a contest to see who could have sex with the most men in one night.
Messalina won.
Source: A Sexual History of London
Picture: Messalina and her son, Britannicus- The Louvre