Input (grade 12): The ballet premiered on 25 May 1870 at the ThÃ Ã cents tre ImpÃ rial de lÂ OpÃ ra, with Giuseppina Bozzacchi in the principal role of Swanhilde.
Output (grade 8): The ballet was first performed in 25 May 1870 at the ThÃ Ã cents tre ImpÃ rial de lÂ OpÃ ra in Paris.