The Rogers and Hammerstein stage musical "Oklahoma!" is frequently cited by Broadway aficionados as the first modern musical - the first to not just stop the story dead in its tracks for each break into song, but to instead integrate those songs into the story, and at times even use them to advance the plot.
The problem with this theory is this: "Oklahoma!" debuted in 1943 - six years after the premiere of Snow White and the Seven Dwarfs.
"We should set a new way to use music," Walt Disney told his story team during the film's production. "Weave it into the story so somebody doesn't just burst into song."
The songs, by Frank Churchill and Leigh Harline, accomplish this goal. Snow and the Prince meet and fall in love during "I'm Wishing/One Song," the princess overcomes her fear of the forest and is lead to the dwarf's cabin during "Smile and a Song," and performs the tasks that will endear her to the seven little men during "Whistle While You Work."
Sure, not every musical moment is a big leap forward in plot (the whole point of "A Silly Song" is how little it matters, really), but then, "Oklahoma!'s" "The Farmer and the Cowman Should be Friends" doesn't exactly advance the story either.
So while it may be technically true that "Oklahoma!" was the first stage musical to use integrated, plot forwarding songs, the next time you hear someone reprise that little nugget you can remind them that Roger's and Hammerstein's classic was beaten to that revolution by a film that was revolutionary in so very many ways: Snow White and the Seven Dwarfs.