The capulets and the Montagues have caused troubles for the prince before.

I can't find a line in the book to help me prove this.

Someone help me find it?

2 answers

Try this useful site.

http://nfs.sparknotes.com/romeojuliet/
Romeo & Juliet:

Act I, Scene I, the Prince says: By thee, old Capulet, and Montague,
Have thrice disturb'd the quiet of our streets,

Sra