Shakespeare's primary source for Romeo and Juliet was Arthur Brooke's Romeus and Juliet, first published in 1562, two years before Shakespeare's birth, and reprinted in 1587, about eight years before the first performance of Romeo and Juliet.

http://www.shakespeare-navigators.com/romeo/BrookeIndex.html

http://en.wikipedia.org/wiki/The_Tragicall_History_of_Romeus_and_Juliet

Love hath inflaméd twain by sudden sight,
And both do grant the thing that both desire
They wed in shrift by counsel of a friar.
Young Romeus climbs fair Juliet's bower by night.
Three months he doth enjoy his chief delight.
By Tybalt's rage provokéd unto ire,
He payeth death to Tybalt for his hire.
A banished man he 'scapes by secret flight.
New marriage is offered to his wife.
She drinks a drink that seems to reave her breath:
They bury her that sleeping yet hath life.
Her husband hears the tidings of her death.
He drinks his bane. And she with Romeus' knife,
When she awakes, herself, alas! she slay'th.