Who refused Romeo's love and caused his depression?

In William Shakespeare's play "Romeo and Juliet," it was Rosaline who refused Romeo's love, leading to his initial depression at the beginning of the play. Romeo's unrequited love for Rosaline is what sets the stage for his eventual meeting and falling in love with Juliet. Rosaline's rejection of Romeo's love serves as a catalyst for the events that unfold throughout the rest of the play.