Seventy-seven years ago on May 15, McDonald’s opened its first restaurant in the world – in San Bernardino, California. The modest hamburger restaurant opened by Richard and Maurice McDonald was a far cry from the global behemoth that the fast food chain is today.

While it initially followed other restaurants with customers being waited on by the staff, McDonald’s soon switched to a “speedy system” and streamlined the experience. Self-service and fewer offerings on the menu, coupled with assembly line production, ensured the success of the original restaurant. Prices were low, and costs were lower.

In 1953, the McDonald brothers offered the first franchising opportunity, and the rest, as they say, was history. Ray Kroc, a milkshake salesman, oversaw the expansion, which saw it transition from being a fast food business to a real-estate one. Much of this story was fictionalised with dramatic license in The Founder, which starred Michael Keaton.

What happened afterwards is a matter of debate, furiously contested by both parties. Kroc gleefully claimed that he “ran the brothers out of business” in a 1973 interview to TIME. He also stated that he partnered with the brothers for the name. “I needed the McDonald name and those golden arches,” Kroc said. “What are you going to do with a name like Kroc?”

In response to the interview, the brothers wrote a letter to the editor, categorically denying the claim: “Ray was also being facetious when he told your reporter that he drove us out of business. My brother and I had retired two years previous to the sale, and were living in Santa Barbara, Calif. We had turned the operation of the San Bernardino unit over to a couple of longtime employees of ours who operated the drive-in for seven years. Ray Kroc was always a great prankster and probably couldn’t resist the temptation to needle me.”

In 1960, Kroc bought the company from the brothers for $2.7 million. Years later, according to a New York Times obituary of Richard McDonald, when asked if he had any regrets, he replied, “I would have wound up in some skyscraper somewhere with about four ulcers and eight tax attorneys trying to figure out how to pay all my income tax.”