 Such grounds, and even the definition of pornography, have differed in various historical, cultural, and national contexts.Social attitudes towards the discussion and presentation of sexuality have become more tolerant in Western countries, and legal definitions of obscenity have become more limited, beginning in 1969 with "Blue Movie" by Andy Warhol, the first adult erotic film depicting explicit sexual intercourse to receive wide theatrical release in the United States.It was followed by the Golden Age of Porn (1969–1984), in which the best quality pornographic films became part of mainstream culture.