"Did my heart love till now? for I ne'er saw true beauty till this night."
This line alludes to the myth of Cupid, the Roman god of love. Romeo is implying that he has never truly loved before, but seeing Juliet for the first time, he feels a love as powerful as the love Cupid inspires.
Here's why it's an allusion:
* Reference to a well-known story: Cupid is a widely recognized figure in mythology, and Romeo's statement makes a direct reference to him.
* Comparison: Romeo compares his feelings for Juliet to the powerful love attributed to Cupid.
* Figurative language: The allusion adds a layer of poetic and dramatic effect to Romeo's declaration.
While other quotes in Romeo and Juliet might include references to other works, this one clearly exemplifies the use of allusion in the play.