He became a naturalized American citizen in 1942. He is remembered for his successful on-screen partnership with Olivia de Havilland. They appeared together in eight movies: "Captain Blood" (1935, his first great success), "The Charge of the Light Brigade" (1936), "The Adventures of Robin Hood" (1938), "Four's a Crowd" (1938), "Dodge City" (1939), "The Private Lives of Elizabeth and Essex" (1939), "Santa Fe Trail" (1940), and "They Died with Their Boots On" (1941). This partnership started rumors of romance. De Havilland denied these rumors. She said her relationship with Flynn was one of friendship only.