Task: Question Generation
Input (English): Passage: In the 1930s, Walton's relationship with the Sitwells became less close. He had love affairs and new friendships that drew him out of their orbit. His first long affair was with Imma von Doernberg, the young widow of a German baron. She and Walton met in the late 1920s and they were together until 1934, when she left him. His later affair with Alice, Viscountess Wimborne (born 1880), which lasted from 1934 until her death in April 1948, caused a wider breach between Walton and the Sitwells, as she disliked them as much as they disliked her. By the 1930s, Walton was earning enough from composing to allow him financial independence for the first time. A legacy from a musical benefactress in 1931 further enhanced his finances, and in 1934 he left the Sitwells' house and bought a house in Belgravia.Walton's first major composition after Belshazzar's Feast was his First Symphony. It was not written to a commission, and Walton worked slowly on the score from late 1931 until he completed it in 1935. He had composed the first three of the four movements by the end of 1933 and promised the premiere to the conductor Hamilton Harty. Walton then found himself unable to complete the work. The end of his affair with Imma von Doernberg coincided with, and may have contributed to, a sudden and persistent writer's block. Harty persuaded Walton to let him perform the three existing movements, which he premiered in December 1934 with the London Symphony Orchestra. During 1934 Walton interrupted work on the symphony to compose his first film music, for Paul Czinner's Escape Me Never (1934), for which he was paid £300.After a break of eight months, Walton resumed work on the symphony and completed it in 1935. Harty and the BBC Symphony Orchestra gave the premiere of the completed piece in November of that year. The symphony aroused international interest. The leading continental conductors Wilhelm Furtwängler and Willem Mengelberg sent for copies of the score, the Chicago Symphony Orchestra premiered the work in the US under Harty, Eugene Ormandy and the Philadelphia Orchestra gave the New York premiere, and the young George Szell conducted the symphony in Australia.
Output (English): What were the last names of the two people who met in the late 1920s and were together until 1934?