Romeo and Juliet
How we cite our quotes:
Two households, both alike in dignity,
In fair Verona, where we lay our scene,
From ancient grudge break to new mutiny,
Where civil blood makes civil hands unclean. (Prologue)
In the Prologue, the Chorus tells us that Romeo and Juliet is a play about domestic conflict. "Two households" (that would be the Montagues and the Capulets), "both alike in dignity" (of the same social standing) are going to be involved in a rather messy, and uncivil family feud. Keep reading…
[…] From forth the fatal loins of these two foes
A pair of star-cross'd lovers take their life;
Whole misadventured piteous overthrows
Do with their death bury their parents' strife.
The fearful passage of their death-mark'd love,
And the continuance of their parents' rage,
Which, but their children's end, nought could remove,
Is now the two hours' traffic of our stage;
The which if you with patient ears attend,
What here shall miss, our toil shall strive to mend. (Prologue)
Here's a little more background for us: children from the feuding families are going to meet and fall in love, putting an end to their families' strife—in the most tragic way remotely possible.
O Romeo, Romeo! wherefore art thou Romeo?
Deny thy father and refuse thy name;
Or, if thou wilt not, be but sworn my love,
And I'll no longer be a Capulet.
Juliet struggles with the conflict between her feelings for Romeo and her knowledge that he is an enemy of her family. She tries to separate Romeo from his identity as a Montague, and contemplates deserting her family for him. She does not imagine that their love and their families' opposition can be reconciled.
Pro tip: When Juliet asks "wherefore art thou Romeo," she's not wondering about Romeo's physical location. "Wherefore" means "why" so, Juliet is basically asking why the love of her life has to be Romeo Montague, the son of her family's enemy.