'Le Nozze di Figaro' is one of the three 'da Ponte' opera's which Mozart composed on libretto's of Lorenzo da Ponte (1749-1838) the famous Viennese theaterdirector and courtpoet. The aria 'L'ho perduta' is sung by Barbarina (the gardener's daughter) at the beginning of the fourth act of the Opera: She is worried because she has lost the pin that was stuck in the letter which Susanna slipped to the Count during the wedding dance.