 On 4 November 1918, one week before the Armistice of Villa Giusti, he became an Italian prisoner of war.After returning to Austria, he attended the University of Vienna, where he earned his Ph.D. in 1920, with a thesis written under the supervision of Gustav von Escherich and Wilhelm Wirtinger.In autumn 1928 he married his first wife Klara Riccabona, who later died while giving birth to their sixth daughter.