Died in Paris on 31 May 1947
He received his first musical instruction with Lavignac and Laforge. Between 1910 and 1917, he was the altoist of the Capet quartet. He also directed the "Théatre de la Gaité Lyrique" in Paris and the Liège Opera (Belgium). Charged with diplomatic and artistic missions abroad, mainly in the USA, he founded, in 1901, in collaboration with Camille Saint-Saîns, the Society of Ancient Instruments (la Société des Instruments Anciens) aimed at reviving on 17th and 18th century instruments, unknown musical works from the masters of the time. Between 1901 and 1939 , the society travelled 350 000 km, performing in many countries, including Russia and the USA. Among its members, it counted: Henri Casadesus (viola d'amore), Marius Casadesus (quinton), Régina Patorni-Casadesus (harpsichord), Lucette Casadesus (viola da gamba) and Maurice Devilliers (bass-viol).
In the course of his travels, Henri Casadesus assembled a remarkable collection of rare and ancient instruments which is currently housed by the Museum of Symphonic Orchestra in Boston.
Five children : Catherine, Jacqueline (with Renée Delerbat) Christian, Gisèle (with Marie-Louise Beetz) Bernard (with Jeanne Montange)
He authored several operettas ("Le Rosier", "Sans tambour, ni trompette", "La petite-fille de madame Angot", "Cotillon III"), melodies, pieces of film music ("Le gardian", "Les mystères de Paris", "Paris-New-York") and a book titled "Méthode de la viole d'amour".