 He then studied from 1922-24 at the "Staatliche Kunstakademie" in Berlin, in the studio of German architect Hans Poelzig which influenced his work during 1920s.His first significant project, the District Labour Insurance Building in Zagreb (1923), was the first project to reflect the spirit of the modern architectural movement in Yugoslavia.Between 1925 and 1935, he established the so-called "Zagreb school of architecture" with fellow architects Drago Galić, Mladen Kauzlarić, Stjepan Planić and others.