For, by your leaves, you shall not stay alone. Till Holy Church incorporate two in one.
Romeo sneeks to Juliets house and asks her to marry him. Romeo is confident that she will say yes.
Romeo talks to Friar Lawrence about marrying Juliet. Friar Lawrence believes the two are rushing into it, but agrees to do it because it could bring peace between the rivaling Capulet and Montague houses.
Romeo and Juliet are married by Friar Lawrence. This is ultimitley leading to their death and the climax. This was the battle before the war.