Alfred Arnstein was born in Vienna on 26 June 1886 as the son of the lawyer Emanuel Arnstein and Regina Hahn. He married Hildegard Arnstein, née Baum, in 1920.
Julius Drey was born in Vienna on 1 May 1858, the son of Lazarus Drey and Babette, née Cohn. He studied in the Medical Faculty of the University of Vienna and completed his doctorate in 1882.
Adolf Irtl studied medicine and after being awarded a doctorate in medicine and surgery in 1892 opened a medical practice at Alser Straße 16 in Vienna's 9th district.
Richard Löwi studied in the Faculty of Medicine of the University of Vienna, where he obtained his doctorate in 1905. In 1907 he opened a general practice at Novaragasse 20 in Vienna's 2nd district, where he also lived with his family.
Oskar Reichel, a Jewish doctor living in Vienna, was a major art collector. He was inspired to start collecting by the works of the Austrian painter Anton Romako, which he says he saw for the first time around 1900.
Sigmund Stiassny was the only son of the Viennese architect Wilhelm Stiassny (1842–1910) and his wife Julia, née Taussig (1848–1916). In 1899 he married Laura Kohnberger and had two children with her, Elisabeth (1901–1986) and Walther Stiassny (1902–1912).
Josef Thenen was born on 21 August 1866 in Galati in present-day Romania into a Jewish merchant family. He had a sister Carolina and a brother Adolf.