older half-sister Paolina, moved in with Vivaldi and regularly accompanied him on his many travels. There was speculation as to the nature of Vivaldi's and Girò's relationship, but no evidence exists to indicate anything beyond friendship and professional collaboration. Vivaldi, in fact, adamantly denied any romantic relationship with Girò in a letter to his patron Bentivoglio dated 16 November 1737. Late period At the height of his career, Vivaldi received commissions from European nobility and royalty, some of them are: The serenata (cantata) Gloria e Imeneo (RV 687), was commissioned in 1725 by the French ambassador to Venice in celebration of the marriage of Louis XV, when Vivaldi was 48 years old. The serenata, La Sena festeggiante (RV 694), was written in 1726 for and premiered at the French embassy as well, celebrating the birth of the French royal princesses, Henriette and Louise Élisabeth. Vivaldi's Opus 9, La cetra, was dedicated to Emperor Charles VI. In 1728, Vivaldi met the emperor while the emperor was visiting Trieste to oversee the construction of a new port. Charles VI admired the music of the Red Priest so much that he is said to have spoken more with the composer during their one meeting than he spoke to his ministers in over two years. He gave Vivaldi the title of knight, a gold medal and an invitation to Vienna. Vivaldi gave Charles a manuscript copy of La cetra, a set of concerti almost completely different from the set of the same title published as Opus 9. The printing was probably delayed, forcing Vivaldi to gather an improvised collection for the emperor. His opera Farnace (RV 711) was presented in 1730; it garnered six revivals. Some of his later operas were created in collaboration with two of Italy's major writers of the time. Vivaldi was accompanied by his father and traveled to Vienna and Prague in 1730. L'Olimpiade and Catone in Utica were written by Pietro Metastasio, the major representative of the Arcadian movement and court poet in Vienna. La Griselda was rewritten by the young Carlo Goldoni from an earlier libretto by Apostolo Zeno. Like many composers of the time, Vivaldi faced financial difficulties in his later years. His compositions were no longer held in such high esteem as they once had been in Venice; changing musical tastes quickly made them outmoded. In response, Vivaldi chose to sell off sizeable numbers of his