Growing up in the 1980s and 1990s in a nearby suburb of Chicago, I learned three inalienable truths about our pizza. First off, Chicago pizza didn’t look like the pizza on TV. Our pizza was cut into squares instead of triangles. Second, any reputable pizzeria would give you a free medium pizza if you saved up 20 of their menus. And, finally, all pizza orders came with a free liter of RC Cola.

I never questioned any of these facts. They were hard-coded into the DNA of Chicago’s pizza culture.

Even now, as an adult, when I think of what real Chicago pizza should be paired with, I think of RC Cola. I recently began to wonder about the ubiquity of RC Cola in Chicago pizzerias. This couldn’t be a coincidence. It had to be the result of genius marketing, or an RC executive made a deal with the devil. In need of answers, I set out to uncover the truth about how the holy trinity of RC Cola, pizza and Chicago came to be.

Coca-Cola has always had a stranglehold on the soft drink industry. Chicago restaurants ranging from shabby hot dog stands to finer establishments with metal forks carried Coke. With a bottling company located on the south side of the city, it was no surprise that Pepsi could be found in the Chicago area restaurants the Coke juggernaut hadn’t reached. RC was the bronze medalist in the Cola Wars. How did the brand that fought for the scraps of the market share end up in the prime real estate of Chicago pizzerias?

The underdog cola was born in the same state as Coke. In the early 1900s the popularity of bottled soft drinks began to explode. During that time, RC Cola’s founder, Claud A. Hatcher, owned a grocery store in Columbus, Georgia. Since Hatcher’s store was selling so much Coke, he asked his local bottler for a bulk discount. The bottler refused to budge on the price. This infuriated Hatcher. He pledged to never do business with Coca-Cola again and began developing his own line of soft drinks.

The Royal Crown brand was officially born in 1905 when Hatcher began marketing a ginger ale he had formulated. His next creation, a cherry-flavored cola called Chero-Cola, was the forerunner to the RC Cola we know today. In 1933, the company reformulated Chero-Cola to taste better. The new beverage, dubbed Royal Crown Cola, was a success. By 1940, RC was available in 47 of the 48 states.

The Royal Crown brand continued to evolve. During the 1950s and 1960s, the company became one of the leading innovators of the soft drink industry. It introduced the first diet soft drink, Diet Rite and pioneered the use of the 16-ounce bottle. Not only was The Royal Crown brand the first of the cola companies to distribute canned beverages nationwide, it was also the first to switch to aluminum cans.

In 2000, corporate behemoth Cadbury purchased the RC Cola brand. A few years later, Cadbury spun its beverage business off into a new company, Dr Pepper Snapple Group (DPSG). Today, DPSG owns a wide array of brands including several regional favorites like 7Up, Vernors, Schweppes, Squirt, Yoo-Hoo, A&W and Sunkist.

I had the opportunity to speak on the phone with Brad Troutman, the Area Director for DPSG based in Chicago. Troutman helped confirm what I had suspected all along, RC Cola’s placement in Chicago pizzerias wasn’t a coincidence.

Troutman explained that RC’s ubiquity with Chicago pizzerias is the result of a shrewd marketing strategy. The local RC bottler based at 47th and California came up with the plan. The bottling company saw an opportunity in the increasing number of pizzerias opening throughout the Chicago in the 1960s and 1970s. They knew that getting RC into local pizzerias could get the cola into consumer’s homes. Providing pizza patrons with free one-liter bottles of RC Cola would be a massive home trial program, planting the seeds of the RC brand in the minds of consumers. A halo effect would strengthen the brand. Consumers would associate their positive feelings about pizza with RC Cola.

For the plan to work, Royal Crown would have to stand out from other vendors. In the 1960s and 1970s the unique nature of the pizza business gave RC’s delivery drivers a chance let the Royal Crown brand shine. Grocery stores would open in the morning, and other restaurants were open by lunchtime. Many pizzerias wouldn’t open until the evening. These pizzerias would accommodate vendors by accepting deliveries at times when they weren’t even open.

Royal Crown eliminated this hassle and made pizzerias high priority customers. Drivers scheduled deliveries at the times that were best for each pizzeria. They also ensured that RC was always in stock, so that the pizzerias knew they could count on the brand.

This higher level of service built a strong relationship between the drivers and the pizzerias. In time, some pizzerias even trusted their RC delivery driver with keys to the restaurant. This trust allowed the driver to make delivery as part of his normal route.

The formula for success was beautifully simple. RC employees would endear themselves to pizza makers. In turn, pizza makers would be happy to push RC products alongside their own. The warm and fuzzy feelings would move down the supply chain to consumers.

Of course, warmth and fuzziness are only part of an effective marketing mix. Price is critical. I’ve always assumed that pizzerias paid next to nothing for RC, encouraging them to give away the one-liter bottles. Troutman declined to discuss price. He would only say that “cost was not a driving factor” in RC’s ascent to Chicago pizza glory.

I took my question on the price of RC Cola to Sam Zaccaro who opened Pozzillo’s Pizza in Schiller Park in 1985. He owned the northwest suburban pizzeria for 21 years before selling the business. Today, he works at his brother Jack Zaccaro’s restaurant, Caruso’s Pizza in Des Plaines.

“It was actually cheaper. It’s still cheaper,” said Sam Zaccaro, “Back when we first started, it was 25 cents a bottle.”

When Pozzillo’s was in business, all pizzas came with a free one-liter bottle of RC. Caruso’s maintains Pozzillo’s tradition for orders over $12. For twenty-years, the minimum order for a free liter of RC at Caruso’s stood at $10! Jack explained that the increase in the order minimum was due to rising costs. Today, a one-liter bottle of RC costs Caruso’s 73 cents.

It wasn’t only price that set RC apart from its competitors–just as the RC bottler based at 47th and California had suspected it was also convenience.

“They started the one liters,” Sam said. He noted that, at the time, Coke and Pepsi weren’t available in one-liter bottles that were convenient for drivers to carry.

Free RC proved to be an effective marketing tactic for both of the brother’s businesses. In the early years, a bottle of RC was even pictured on the cover of Pozzillo’s menu to entice customers.

“People get crazy about their free pop,” said Tommy Meyers, who delivers for Caruso’s. Customers strive to reach the $12 minimum order.

“People will buy a $2 order of fries for a $1.75 bottle of pop,” Sam explained.

Countless pizzerias in the Chicago area saw the value of offering a free liter of RC, and everyone involved benefited. Pizzerias sold more pizzas and, just like in the example that Sam cited, add-ons like fries. Customers got free pop to pair with their pizzas and Royal Crown found a Trojan horse into the customers’ homes and hearts.

“For decades, RC Cola has been synonymous with Chicago culture,” said Troutman, adding that Chicago is the country’s biggest market for RC.

RC’s place in Chicago’s culture continues to grow. In 2012, DPSG struck a deal with the Bears and RC Cola and Dr Pepper replaced Coke as the exclusive cola served at Soldier Field.

It’s no surprise that many Chicagoans feel that RC’s place in Chicago pizza lore is about more than just business.

“RC actually goes with pizza,” Sam said. “I don’t know what it is. Nothing else really tastes the same.”

I couldn’t agree more.