Question

who was portia and why shylock was his enemy

Answer 1

Portia is the wife of basanio.Basanio's friend was Antonio.Antonio needed money for basanio's trip to meet portia.Since Antonio's ships where at sea, he was in a time to get money from Shylock,a jewish money lender who was very selfish.
He made Antonio to sign a boned stating that if antonio was unable to return the money within 3 months then Shylock shall cut a pound of flesh from near his heart.
But Antonio was unabled to repay the money.So he was in a case and portio on account of antonio's help to her , came as a lawyer and helped antonio.

Answer 2

Portia was the heir to all the riches to her dead father...her life fate was sealed in the lottery decided by her father.... she could not choose a husband she likes nor refuse a husband she does not like... at this point bassanio comes and chooses the right casket therefore winning her and all her riches as the prize... bassanio's friend antonio was the one who provided the means of money for bassanio to compete in the competition and he risked his life in order to do so... antonio 's riches were invested on the goods across the sea and it did not come in time for antonio to return the money... so his bitter enemy took this opportunity to kill him and take his revenge...portia , now the wife of bassanio, considers a dear friend of bassanio as bassanio itself and provides all the means to rescue him... and portia and her friend nerrissa disguises themselves as lawers and confront shylock who was the bitter enemy of antonio and rescues him...