Both are women, both are wives of key statesmen (Portia - Brutus, Calpurnia - Julius Caesar). Both women try to persuade their husbands and succeed - Portia persuades Brutus to tell her the details of the conspiracy, and Calpurnia persuades Julius Caesar not to go to the capitol because she has had bad dreams.
However, Brutus does tell Portia about the conspiracy (not that it makes any difference) where Caesar, although he does momentarily agree not to go to the capitol, is soon persuaded around by Decius Brutus.
"How foolish do you fears seem now, Calpurnia", Caesar says, "I am ashamed that I did yield to them" - and that is the last time Calpurnia is ever mentioned in the play. She makes no re-entrance, and is never spoken about after her husband's death.
Portia too meets a sticky end: we find in the quarrel scene between Brutus and Cassius that she commits suicide by swallowing hot coals. She too is never seen on the stage after the murder.
So Portia is the character with the more stage time - a little more self-righteous, a little more forceful, and (the key difference) her persuading is ultimately successful. But both women persuade, both women are largely irrelevant to the political gameplaying of their husband, and both women vanish from the stage: Portia to death, and Calpurnia just vanishes!
Calpurnia is represented by Shakespeare as the humble and obedient wife of Julius Caesar.Her character is important for the following reasons:
1.To contrast the private, domestic life of Caesar with his public political life: Caesar makes his first appearance on the stage in a "nightdress" and the very first lines that Caesar utters refer to his wife, "Thrice hath Calpurnia in her sleep cried out/'Help ho! they murder Caesar." From the beginning of the play till now all that we have heard about Caesar relates to his warrior like and statesman like qualities. But, Shakespeare foregrounds his first appearance on the stage by presenting him as a worried and anxious husband who is ready to please her initially by agreeing not to go to the Senate,"and for thy humour I will stay at home."
2.To contrast fate and human will: Calpurnia's intuitive fears,"O Caesar these things are beyond all use/And I do fear them," are contrasted with Caesar's self confidence, "It seems to me most strange that men should fear/Seeing that death a necessary end/Will come when it will come."
3. Calpurnia's interpretation of her dream is brushed aside and Decius' interpretation is accepted by Caesar to emphasise the significance of the public and the political over the private and the domestic, "How foolish do your fears seem now, Calpurnia."
4.Calpurnia represents the fear and the superstitious beliefs of the contemporary Elizabethan audience concerning the supernatural.
Like Calpurnia, Portia is also a very humble and obedient wife. However, since Brutus is also a conspirator who is under a lot mental stress because of his plans to assassinate Caesar his relationship with his wife is strained and tense. The obvious reason being he cannot reveal and discuss the finer details of the conspiracy with his innocent wife Portia. This tension is palpable in Act II when Portia on bended knee begs of her husband to know the reason why he has not slept that night. Brutus offers evasive replies, and fortunately for him Ligarius, whom he had sent for, is heard knocking at his door. Brutus hurriedly asks Portia to leave saying that he will reveal everything to her later, "and by and by thy bosom shall partake/The secrets of my heart...Leave me with haste." And she being the obedient wife does so.
After Caesar's assassination and the consequent civil war, Brutus is fully involved in public affairs and circumstances force him to completely ignore his wife with tragic consequences. In ActIV sc.3, Brutus tells Cassius how pitiably she died. Brutus tells Cassius that Portia died by swallowing hot coals. Since Brutus had been away on his military campaign and on hearing that Octavius had joined forces with Antony, she had become very upset and mentally distracted. When she was left unattended she swallowed hot coals of fire and died:I
"Impatient of my absence,
And grief that young Octavius with Mark Antony
Have made themselves so strong:--for with her death
That tidings came;--with this she fell distract,
And, her attendants absent, swallow'd fire."
In marked contrast we never learn from the play how Calpurnia died.
To conclude, both Calpurnia and Portia are important inasmuch as they reveal more of the personalities of their husbands than about themselves.
Some of the similarities between Calpurnia and Portia are:
*They are the wives of important men in Rome's society
*Their warnings of impending doom are ignored by the men they love
*They are both given relatively small roles within the play and serve as the voice of caution and foreshadowing as each woman suspects that horrible things will befall their husbands
Some of the differences between Portia and Calpurnia are:
*Calpurnia's worry is brought on by strange dreams and images of nature while Portia's worry is brought on by logical deduction as she observes her husband's secret meetings and odd behavior an concludes that something is amiss
*Calpurnia listens to her husband and ceases her attempts to stop him from leaving for the forum. Portia supposedly listens to her husband but actually has a messenger boy sent out to spy on Brutus for her
*Portia is praised, honored and appreciated by her husband (2.1) who wishes to become worthy of her. Calpurnia is not appreciated by Caesar because she cannot bear children and treated more like an ornament than a partner in marriage
if you want to compare each character, you must look at the way they handle situations they are faced with but in this play, the how they respond to the treatment they receive from their husbands are also necessary...
calpurnia for one is soft spoken, quiet and fades into the background until her character is needed to forshadow events to come, this is because of caesar's fits of anger that we have been introduced to. one occasion being right after the feast of lupercal, when he is offered the crown thrice and is returning, it is noted that his entourage seems pale and act as if they had been shouted at. calpurnia also bears with the embarrassment she received because of caesar on two occasions ( one being when her barreness is made public because caesar made antony touch her during the race and the other is when she convinces him to stay at home because of her dream but she is made to look foolish in front of decius
portia on the other hand is outspoken