1984 was a strange time for American movie musicals. They weren’t exactly extinct; for the third year in a row, the Oscars found enough nominees to present an award for Original Song Score (basically, best lineup of songs, rather than sole Original Song or Original Score). Yet at the same time, the genre had been transformed by a more realism-focused 1970s, a more spectacle-driven 1980s, and a belated embrace of pop music.

As a result, the summer of ’84 came alive with movie music, but only the Muppets were really holding it down for traditional showtunes (in The Muppets Take Manhattan , consciously a throwback to old-timey showbiz musicals). Elsewhere, you had Dolly Parton, who might have been a consistent musical movie star in previous generations, teaming up with Sylvester Stallone in Rhinestone ; dance musicals like the summer mini-sensation Breakin’ and the still-playing Footloose ; and bizarre attempts to embody the spirit of rock and roll like future cult object Streets of Fire . The biggest musical of the year landed in (or close to) that last category when it emerged in July 1984: Purple Rain , a hybrid of backstage musical, concert movie, and premature biography featuring pop genius Prince – and winner of that year’s Original Song Score Oscar, handily beating the Muppets.

40 years later, Purple Rain feels both singular and influential. Perhaps most notably, it also feels like a creative evolution of the movie musical, even if not many subsequent projects f.