However, in the early 20th century, theorists, such as Sommerfeld at Munich and Max Born at the University of Göttingen, with their early training in mathematics, turned this around so that mathematical physics, i.e., theoretical physics, became the prime mover, and experimental physics was used to verify or advance theory.
V Göttingenu je Sommerfeld srečal Johanno Höpfner, hčer Ernsta Höpfnerja, skrbnika v Göttingenu.