Sigmund Freud's theories were shaped by the societal influences of late 19th-century Vienna, which was characterized by conservative views on sexuality and gender roles. He developed his ideas on psychosexual development and unconscious motivations in response to the repression of sexual expression at the time. Freud's background in neurology and exposure to medical practices also informed his psychological theories. The cultural context of Viennese intellectual circles contributed to his exploration of dream analysis and the psyche, marking a significant shift in the understanding of mental health.