[4][5] Another Union-Theater was opened at Berlin's Unter den Linden on 21 August 1910, by 1910 Davidson had built up a "sizeable chain of 600–1000 seater luxury cinemas".

[6] On 2 August 1913 the Union-Palast, Kurfürstendamm, one of the first buildings of Berlin exclusively built as a movie theater, premiered with Max Reinhardt’s "Die Insel der Seligen".

[6][7] In March 1910 Davidson founded the Projektions-Aktiengesellschaft Union (PAGU), Germany’s first joint-stock company in film industry and the first to integrate production, distribution and equipment hire.

[11] The PAGU engaged directors like Ernst Lubitsch and Paul Wegener as well as actors like Asta Nielsen, Fern Andra, Pola Negri, Ossi Oswalda, Emil Jannings and Harry Liedtke.

[1] In January 1914 PAGU was merged with Jules Greenbaum’s company to form PAGU-Vitascope, however, the project, including a cooperation with the French Pathé Freres ended at the outbreak of World War I.

[12] In 1920 he left the UFA to produce Lubitsch’s "Das Weib des Pharao" (The Wife of the Pharaoh) and "Die Flamme" (The Flame) within the short-living Europäische Film-Allianz (EFA).