After Italy's declaration of war on Austria in 1915, Switzerland had found itself completely surrounded by warring powers. The trenches of the Western Front reached from Basel to the North Sea, while battles less famous—but hardly less bloody—raged on its southern borders (the chaos on that front being vividly depicted by Ernest Hemingway in his A Farewell to Arms). Switzerland's longstanding neutrality continued to be respected by the nations at war, so most of those in Central Europe who wished to avoid participation in the general slaughter inevitably endeavored to reach Swiss soil, with Zurich the city of choice for many of them. By the end of 1916, the city comprised just fewer than 150,000 Swiss citizens and almost 60,000 foreigners. The economy of the city suffered dreadfully during the four years of the conflict, so it is a considerable testament to the tolerance of the local populace that relations between Swiss and foreigners remained largely cordial throughout.

Such a wave of immigration also brings with it an immense stimulus to a city's intellectual and cultural life. Zurich had experienced a similar upswing after the European revolutions of 1848 and 1849 that had brought Richard Wagner, Gottfried Semper, and others to the city, but World War I brought a far greater number of artists and intellectuals than could have been imagined. They were joined in the cafés, restaurants, and theaters of the city by the leading Swiss artists of the day.