Italian opera soprano singer, actress, and monologist, in her time referred to as the “world’s most beautiful woman.”
She lost her parents at the age of fifteen and became a ward of the state, sent to live in a Roman Catholic orphanage. The vivacious young girl was unhappy under the strict discipline of the nuns, and at the first opportunity she ran away with a touring theatrical group.
At a young age, she made her way to Paris, France, where she obtained work as a singer at one of the city’s caf‚-concerts. From there she performed at a variety of music halls and other such venues around Europe, while still working to develop her voice. In 1900, she married her first husband, the Russian Prince Alexandre Bariatinsky. In 1904, she sang at the Op‚ra de Monte-Carlo then in 1905, at the Sarah Bernhardt Theatre in Paris, Cavalieri starred opposite Enrico Caruso in the Umberto Giordano opera Fedora. From there, she and Caruso took the opera to New York City, debuting with it at the Metropolitan Opera on 5 December 1906.
Cavalieri remained with the Metropolitan Opera for the next two seasons, performing again with Caruso in 1907, in Puccini’s Manon Lescaut. Renowned as much for her great beauty as for her singing voice (and acting ability), she became one of the most photographed stars of her time.
Her first marriage long over, she had a whirlwind romance with Robert Winthrop Chanler (1872?1930), a member of the Astor family and Dudley?Winthrop family. They married on 18 June 1910 but separated by the end of their honeymoon, and their divorce became final in June 1912. After the divorce, Cavalieri returned to Europe where she became a much-loved star in pre-revolutionary St. Petersburg, Russia, and in Ukraine. She married French tenor Lucien Muratore in 1913.
After retiring from the stage, Cavalieri ran a cosmetic salon in Paris. In 1914, she wrote an advice column on make-up for women in Femina magazine and published a book, My Secrets of Beauty. In her parisian Institut de Beaut‚, she licensed Parfums Isabey Paris and not only sold Isabey perfumes but developed in 1926 a range of beauty products and launched the same year her own perfume, apparently inspired by Leonardo da Vinci’s Mona Lisa, which she called ‘Mona Lina.’
In 1915, she returned to Italy to make motion pictures. When that country became involved in World War I, she went to the United States where she made four more silent films. The last three of her films were the product of her friend, the Belgian film director Edward Jos‚. Almost all of her films are considered lost films.
After marrying her fourth husband Paolo d?Arvanni, she returned to live with him in Italy. Well into her sixties when World War II began, she nevertheless worked as a volunteer nurse. Cavalieri was killed on 8 February 1944 during an Allied bombing raid that destroyed her home in Florence near Poggio Imperiale, where she was placed under police surveillance because of her foreign husband.

Link to Wikipedia biography