Passage: In 1923, Hesse received Swiss citizenship. His next major works, Kurgast (1925) and The Nuremberg Trip (1927), were autobiographical narratives with ironic undertones and foreshadowed Hesse's following novel, Steppenwolf, which was published in 1927. In the year of his 50th birthday, the first biography of Hesse appeared, written by his friend Hugo Ball. Shortly after his new successful novel, he turned away from the solitude of Steppenwolf and married art historian Ninon Dolbin, née Ausländer. This change to companionship was reflected in the novel Narcissus and Goldmund, appearing in 1930. In 1931, Hesse left the Casa Camuzzi and moved with Ninon to a large house (Casa Hesse) near Montagnola, which was built according to his wishes.

Question: What job did Ninon Dolbin have?
art historian