Courtly love started in the time of King Arthur. His wife fell in love with a friend of his, the lovers met in secret. Most courtly lovers are also married or have other engagements which is the reason they must keep their love in secret. Another example is Romeo and Juliet. He appeared at her window in secret and spoke of the love he felt for her. Neither he or she cared of the other's last name and the duties that came with the names. Married noblewomen would give tockens, such as a jewel, to their lover and they would keep it while trying to proove his love.
Romeo stumbled apon Juliet's window and professed his love to her, even though she was a Capulet. His courtly love was greater than her name and her family.