 The gallery also participated in the Armory Show of 1913, the watershed exhibition that introduced European Modernism to the United States, and mounted the first major Pablo Picasso retrospective during the same year.In 1919, Heinrich Thannhauser's son, Justin K. Thannhauser (1892-1976), established a branch of the gallery in Lucerne (Luzern), Switzerland.He ran the branch until 1921, when he was called back to Munich to assist his father, who had developed a serious condition in his larynx.