In the 1920s, movie palaces rose up around the country like so many portals into a glamorous world. After you bought a ticket, you might pass through gilded archways and ascend a grand staircase lighted by a crystal chandelier to find your velvet seat. Eating was not meant to be part of the experience, says Andrew F. Smith, author of “Popped Culture: A Social History of Popcorn in America.” Theater owners feared that audiences would strew popcorn and peanuts on those crimson carpets. They hung signs discouraging people from bringing in food from vendors parked outside and didn’t sell it themselves.

A widow named Julia Braden in Kansas City, Mo., was one of the rare concessionaires who managed to talk her way inside. She persuaded the Linwood Theater to let her set up a stand in the lobby and eventually built a popcorn empire. By 1931, she owned stands in or near four movie theaters and pulled in more than $14,400 a year — the equivalent of $336,000 in today’s dollars. Her business grew even in the midst of the Depression, at the same time that thousands of elegant theaters went bust.

According to Smith, it’s impossible to establish who sold the first box of movie popcorn. For decades, vendors operated out of wagons parked near theaters, circuses and ballparks, selling a variety of snacks. But Braden seems to have been among the first to set up concessions linked to movie houses — and to pioneer a new business strategy: the money was in popcorn, not ticket sales. (That’s still true today. Movie theaters reap as much as 85 percent of their profits from concession sales.)