His next novel, "Gertrude", published in 1910, revealed a production crisis. He had to struggle through writing it, and he later would describe it as "a miscarriage". Gaienhofen was the place where Hesse's interest in Buddhism was re-sparked. Following a letter to Kapff in 1895 entitled "Nirvana", Hesse had ceased alluding to Buddhist references in his work. In 1904, however, Arthur Schopenhauer and his philosophical ideas started receiving attention again, and Hesse discovered theosophy. Schopenhauer and theosophy renewed Hesse's interest in India. Although it was many years before the publication of Hesse's "Siddhartha" (1922), this masterpiece was to be derived from these new influences.