poet Blaise Cendrars who was to become her friend and collaborator. Sonia Delaunay described in an interview that the discovery of Cendrars' work “gave me [her] a push, a shock.” She illustrated Cendrars' poem La prose du Transsibérien et de la Petite Jehanne de France (Prose of the Trans-Siberian and of Little Jehanne of France) about a journey on the Trans-Siberian Railway, by creating a 2m-long accordion-pleated book. Using simultaneous design principles the book merged text and design. The book, which was sold almost entirely by subscription, created a stir amongst Paris critics. The simultaneous book was later shown at the Autumn Salon in Berlin in 1913, along with paintings and other applied artworks such as dresses, and it is said that Paul Klee was so impressed with her use of squares in her binding of Cendrars' poem that they became an enduring feature in his own work. Spanish and Portuguese years (1914–1920) The Delaunays travelled to Spain in 1914, staying with friends in Madrid. At the outbreak of the First World War in 1914 Sonia and Robert were staying in Hondarribia, in the Basque Country, with their son still in Madrid. They decided not to return to France. In August 1915 they moved to Portugal, where they shared a home with Samuel Halpert and Eduardo Viana. They discussed an artistic partnership with Viana and their friends Amadeo de Souza-Cardoso, whom the Delaunays had already met in Paris, and José de Almada Negreiros. In Portugal she painted Marché au Minho (Market in Minho, 1916), which she later says was "inspired by the beauty of the country". Sonia had a solo exhibition in Stockholm (1916). The Russian Revolution brought an end to the financial support Sonia received from her family in Russia, and a different source of income was needed. In 1917 the Delaunays met Sergei Diaghilev in Madrid. Sonia designed costumes for his production of Cleopatra (stage design by Robert Delaunay) and for the performance of Aida in Barcelona. In Madrid she decorated the Petit Casino (a nightclub) and founded Casa Sonia, selling her designs for interior decoration and fashion, with a branch in Bilbao. She was the center of a Madrid Salon. Sonia Delaunay travelled to Paris twice in 1920 looking for opportunities in the fashion business, and in August she wrote a letter to Paul Poiret stating she wanted to expand her business and include some of his