Role in the story
Portia is beautiful, gracious, rich, intelligent and quick-witted, with high standards for her potential romantic partners. She is bound by the lottery set forth in her father's will, which gives potential suitors the chance to choose between three caskets composed of gold, silver and lead. If they choose the right casket – the casket containing Portia's portrait and a scroll – they win her hand in marriage. If they choose the incorrect casket, they must leave and never seek another woman in marriage. Portia is glad when two suitors, one driven by greed and another by vanity, fail to choose correctly, although she demonstrates tact to the Princes of Morocco and Arragon, who unsuccessfully seek her hand. She favours Bassanio, a young Venetian noble, but is not allowed to give him any clues to assist in his choice.
Later in the play, she disguises herself as a man, then assumes the role of a lawyer's apprentice (named Balthazar) whereby she saves the life of Bassanio's friend, Antonio, in court.
In the court scene, Portia finds a technicality in the bond, thereby outwitting the Jewish moneylender Shylock and saving Antonio's life from the pound of flesh demanded when everyone else including the Duke presiding as judge and Antonio himself fails. It is Portia who delivers one of the most famous speeches in The Merchant of Venice:
The quality of mercy is not strain'd.
It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blest:
It blesseth him that gives and him that takes.
Despite Portia's lack of formal legal training, she wins her case by referring to the details of the exact language of the law. Her success involves prevailing on technicalities rather than the merits of the situation. She uses the tactics of what is sometimes called a Philadelphia lawyer in modern times and in so doing demonstrates that she is far from powerless, irrespective of her earlier lack of choice in the marriage. However, the concept of rhetoric and its abuse is also brought to light by Portia – highlighting the idea that an unjust argument may win through eloquence, loopholes and technicalities, regardless of the moral question at hand – and thus provoking the audience to consider that issue. Shylock leaves the trial with both his life and his job intact but retains only half of his money and is deprived of his identity on being forced to convert to Christianity, while his daughter Jessica and her Christian husband Lorenzo with whom she had previously eloped are found in Portia's castle, not, it is implied, in complete happiness. Portia and Bassanio, on the other hand, continue to live together along with the former's lady-in-waiting Nerissa and her husband Gratiano.