 Robert's German-Jewish father Ludwig "Elieser" Binswanger (1820-1880) was founder, in 1857, of the "Bellevue Sanatorium" in Kreuzlingen.Robert's brother Otto Binswanger (1852-1929) was a professor of psychiatry at the University of Jena.Ludwig (1881-1966) is considered the most distinguished of the phenomenological psychologists, and the most influential in making the concepts of existential psychology known in Europe and the United States.