"This was a man" is Antony's final tribute to Brutus. Brutus' reputation, damaged as it has been by his participation in the conspiracy, and by his rather self-deluding rationale for it, has been reclaimed. It has been reclaimed partially because his character, defined at the beginning of the play as entirely masculine, has taken on some feminine characteristics, such as grief over his wife's death, love for his friend, and tender concern for his followers. By the end of the play, Brutus' character is more fully-rounded but is the world he leaves us better off? Can it be when the world left behind is entirely without women? Shakespeare takes the opportunity in Julius Caesar to say both "yes" and "no." At times, characters take on so-called feminine characteristics and lose their ability to rule well. At other times, characters like Brutus gain a great deal from incorporating the feminine into their own personalities. Shakespeare's suggestion is that while a balance can be struck and an ideal attained, it is ultimately unworkable.
You find only two female characters in Julius Caesar. The first, Calphurnia, is Caesar's wife, and is emblematic of one standard sexist Elizabethan understanding of woman. She is a shrew. She controls instead of being controlled. She exists as a foil for her husband's character. By her strength, the audience sees what Caesar ought to be; by her conscience, what his ought to be; by her death, what he ought to be prepared to do. For this reason, her character is not developed on a psychological level in the way that Caesar's is.
The reader's first contact with her is during the feast of Lupercal. Caesar asks Antony to touch her as he passes her in the race that is a part of the celebrations. Caesar asks this because Calphurnia is childless, and superstition dictates that the touch of the athlete during this holy feast will make her fertile. The implication, then, is that she is at fault for not producing an heir. In fact, the implication is that Caesar is no longer potent enough to impregnate her. His request of the athletic womanizer, Antony, is an indication of Caesar's own effeminacy.
Such is the root of Caesar's downfall. He has taken on too many feminine characteristics. His prowess is in the past and is only momentarily evident in Act II, Scene 2 when he refuses to listen to Calphurnia's worries about what will happen if he goes to the Capitol. "Caesar shall forth. The things that threatened me / Ne'er looked but on my back; when they shall see / The face of Caesar, they are vanished." However, he is convinced, bowing to her hysteria and his mind is changed only after Decius embarrasses him. "[I]t were a mock / Apt to be rendered for someone to say / 'Break up the Senate till another time, / When Caesar's wife shall meet with better dreams.'" On to his own death.
Portia is a much more interesting character on her own and yet she, too, is really only portrayed through her relationship with men. Her relationship with her husband is clearly one of intimacy and respect. She speaks openly with him about the unrest he has recently exhibited and forces him to speak to her and tell her what is going on.
Note, however, how she does this. Brutus does not want her to know what is going on. She changes his mind by pressing him to define her in one of the two ways in which a woman can be defined in this society: She is either a good Roman woman worthy of his secrets, well-wived and well-fathered, or she is "Brutus' harlot." Faced with this distinction, Brutus can only choose to tell her what is happening. Unfortunately for Portia, the knowledge that he imparts is her downfall. In Act II, Scene 4 Portia complains that she has "a man's mind, but a woman's might." She has been given access to a man's knowledge but because of her position as a woman, she is unable to use it and must sit and wait for the outcome of men's affairs. Such knowledge is too much for her and she commits suicide in the very garden in which she first heard Brutus' secrets.
With this, Portia is gone from the play, and the reader never again sees a female character. What the audience does see, however, is a transference of Portia's feminine qualities to her husband by means of his relationship with Cassius. At the beginning of the play, the relationship between these two men was less than profound. They are connected by a common desire to overturn Caesar's tyranny but have entirely different motivations. In addition, Cassius' approach toward convincing Brutus to join him has been cynical to say the least.
By Act IV, Scene 2, their relationship has become a friendship, and it has become a friendship that has the decided qualities of a love relationship. In Act IV, Scene 2, Brutus has taken offense at what he believes was Cassius' refusal to send money when he needed it. Cassius is quite taken aback by this accusation and the conversation quickly descends into a "yes you did, no I didn't" affair that almost results in a fight. Cassius is innocent of the offense and is hurt that he is "Hated by one he loves, braved by his brother."
What motivates Brutus to this anger? It turns out that it is grief over Portia's death. It is to Cassius that Brutus turns in his grief. The grief that he feels, the loss, the sense of betrayal are all translated into anger toward this friend, and after those emotions are spent, the two men are closer in some ways than Brutus ever was with Portia. The latter relationship shares the same respect for each other and the same sharing of intimacy, yet it is a relationship that can operate in the same spheres because it encompasses a level of equality not possible between a woman and a man.
From that moment, the audience has an increasing amount of sympathy for Brutus, who has been humanized by his wife's death. While he clearly loved his wife, there was also some distance between them, partly because of her rather stoic nature (remember her self-wounding), partly because he is unwilling to confide in her. This combination of the masculine and the feminine in her character was not a completely appropriate one. It was unworkable given the way in which the Roman world worked. The flip side, of course, was Caesar's behavior. His combination of femininity and masculinity was also unworkable. With their deaths, Brutus is able to incorporate both aspects of their personalities, most directly from his wife, given her more moral nature. With the banishment of women and inappropriate femininity from Rome, the state ought to be a better one. But there is an unattractive sterility to such a world. What has been created is an unworkable ideal. Brutus' death is an indication of just how unworkable it is.