Casadesus received his early musical instruction with Albert Lavignac and studied viola with Théophile Laforge at the Conservatoire de Paris, taking first prize in 1899.
Henri Matisse | Henri de la Tour d'Auvergne, Vicomte de Turenne | Bernard-Henri Lévy | Henri Dutilleux | Paul-Henri Mathieu | Henri Poincaré | Robert Henri | Henri Mignet | Henri Cartier-Bresson | Henri Fayol | Henri Bendel | Henri Barbusse | Jean-Henri Fabre | Henri-Pierre Roché | Henri Langlois | Henri, Grand Duke of Luxembourg | Henri Fantin-Latour | Paul-Henri Spaak | Jacques-Henri Bernardin de Saint-Pierre | Henri Wallon | Henri Vieuxtemps | Henri Vernes | Henri Salvador | Henri Pousseur | Henri Michaux | Henri Guillaumet | Henri Estienne | Lycée Henri-IV | Henri Tajfel | Henri Sauguet |
The "Adélaïde Concerto" is sometimes erroneously credited to Marius' brother Henri Casadesus, perhaps because of many other spurious musical pieces he and other members of the Casadesus family penned in the names of Johann Christian Bach, George Frideric Handel, and other composers.