Lucretia is a mythical(?) figure in the history of the Roman Republic.
According to Livy's version of the establishment of the Republic the last king of Rome, Lucius Tarquinius Superbus (superbus, "the proud") had a thoroughly unpleasant son, Sextus Tarquinius, who raped a Roman noblewoman named Lucretia . Lucretia compelled her family to take action by gathering the men, telling them what happened, and killing herself. They then were compelled to avenge her, and led an uprising that drove the Tarquins out of Rome to take refuge in Etruria.
See also Roman Republic.