Two women play substantial roles in William Shakespeare's play Julius Caesar, Calpurnia, the wife of Julius Caesar and Portia, the wife of Brutus.
The first important issue relevant to this question is that all women in Shakespeare's plays were originally played by boys or young men. As Shakespeare was writing for a repertory company, he may well have wanted simply to include roles for his starring actors who specialized in female roles. Often in modern repertory companies plays are chosen or created with the specific composition of the regular actors in mind.
Next, we can see a symmetry in creating the wives of the two leading male characters. In both cases, the wives provide the occasion for the men to discuss the their inner thoughts in a way they could not do in public with other men, given the highly fraught political situation.
The final issue is that both wives act as voices of restraint, with Calpurnia especially trying to dissuade Caesar from going to the forum. In this way, Shakespeare has women symbolize domesticity and peace, with men as a disruptive force. Despite the women trying to maintain the stability of the home (and by extension, the Republic), both men in their own ways function as disruptive forces. In certain ways, this portrayal of women as a force for peace and stability flatters Queen Elizabeth, who like the wives in the play projected a discursive construction of monarchy that emphasized peace and stability.