Portia: Background
Portia was a noble woman living in Rome during Julius Caesar's time period. She was the daughter of Stoic Cato. Portia was also the strong, devoted wife of Brutus, who was a high official to Caesar. During the Julius Caesar play she realizes that Brutus is struggling with something. To prove that Brutus can trust her and that she is as strong as a man, she slashes her thigh. This shows that Portia was a strong, loving, and smart woman during her time period.
Brutus and Portia's relationship is built on being equal. Brutus does not talk down to his wife and she does not talk to him as if he is better than her. Their relationship that they have during the play is not typical of Roman marriages during that time period.
(http://www.shakespeare.about.com/od/studentsources/a/GuideCaesar_2.htm.)