The sibling rivalry behind Kellogg's that created the modern breakfast cereal

• Modern cereal owes its existence to a bitter rivalry between John Harvey Kellogg and his younger brother Will Kellogg, who founded the iconic Kellogg's food brand.
• John Harvey was a renowned doctor in the late 19th century who ran the Battle Creek Sanitarium, a medical facility in Michigan where presidents and celebrities like Thomas Edison, Henry Ford, and Amelia Earhart received treatments to improve their bowel movements.
• John Harvey had his younger brother Will develop the first modern wheat flakes in the 1890s so that patients could have a pre-cooked, ready-to-eat breakfast cereal.
• Recognizing the commercial potential of the new invention, Will bought his brother's cereal business and left the Sanitarium to found the now-iconic brand Kellogg's in 1906.
• Jealous of his brother's success and angry over the commercial use of the Kellogg name, John Harvey set up a competing cereal company, sparking a legal challenge from Will and a lifetime of rivalry.
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You may owe the existence of the cereal in your cabinet to a bitter rivalry between two brothers.

John Harvey and Will Kellogg were born in Michigan in the mid-19th century and had a contentious relationship from the very start. The elder John was seen as brilliant and left home to study medicine in New York. The younger Will was suspected of having low intelligence by his family. John Harvey frequently subjected Will to verbal and physical abuse.

By the time they were adults, John Harvey was a highly regarded doctor and ran a massive medical complex called the Battle Creek Sanitarium in Battle Creek, Michigan.

At the time, Americans were obsessed with healthy bowel movements. John Harvey was at the forefront of this obsession. At the Sanitarium, presidents and celebrities like Thomas Edison, Henry Ford, and Amelia Earhart received treatments intended to improve digestion.

John Harvey hired Will at age 20 to run the business side of the Sanitarium. Under his brother, Will's humiliating treatment continued. He wasn't allowed to have an office. John Harvey called him his "lackey" and forced him to follow him around with a notebook, dictating ideas as they occurred to him. That meant that when John Harvey rode his bike across the Sanitarium campus, Will was forced to run alongside him to keep up. John Harvey even forced Will to come into the bathroom with him to record his thoughts.

"That really, I think, explains the relationship to a T," medical historian Dr. Howard Markel of the University of Michigan told Business Insider. "Will was quiet, but he hated it."

But a menial task from John Harvey eventually led to Will's massive success.

Inventing modern cereal

In the 1890s, pre-cooked, ready-to-eat, safe breakfast cereals did not exist. So John Harvey decided to make some. The gut-obsessed older brother was convinced that if grain was baked at an extremely high heat, its complex sugars and starches would break down and make it easier to digest. That meant Will had to spend hours crouched under a hand-cranked roller, catching flattened dough and chiseling off tiny flakes. That led to what is now a ubiquitous type of cereal: Wheat flakes.

"That was a Eureka moment," Markel said.

Will set up a makeshift factory at the Sanitarium and started selling the flakes in ten ounce packs for 15 cents each. In its first year of production, the brothers sold over 113,000 pounds of flakes.

"It was a huge deal because all of a sudden you could have an instant breakfast poured out of a box, pour milk on it, eat it," Markel said. "Even dad could make breakfast now."

To Will's frustration, John Harvey wasn't interested in exploiting the clear commercial possibilities of their new product. So in the early 1900s, Will started experimenting with a new kind of cereal. He played with different ingredients, like salt and sugar — which John Harvey would never have condoned. Through relentless experimentation he created another iconic food: Corn flakes.

In 1905, after 25 years of working for his brother, Will offered to buy his brother's cereal business. John Harvey, who was in debt and uninterested in marketing his cereals, agreed. The 46-year-old Will Kellogg founded the Battle Creek Toasted Cornflake Company, better known today as Kellogg's.

Battling over the Kellogg name

Will poured millions of dollars into ad campaigns using mascots like Snap, Crackle, and Pop. He sparked his brother's ire when he put the name "Kellogg" on his cereal boxes and started signing his work: Every box was branded with "W.K. Kellogg" in big swoopy red cursive.

"He [John Harvey] hated it," Markel said. "And the fact that Will was doing well. He hated the fact that it was his invention. He hated the fact that he was using the name Kellogg, and their signatures actually were even somewhat similar….he just went nuts."

John Harvey created "The Kellogg Toasted Corn Flake Company'' in 1908 and started selling a version of his brother's product. In 1910, Will asked a judge to put an injunction against his brother for making a Kellogg's-branded cereal, and the two went to court.

The brothers reached a settlement out of court but continued their legal sparring for a decade. When John Harvey started marketing a new "sterilized bran" cereal in 1916, Will immediately made his own version. John Harvey filed a restraining order against his brother, and by 1917 they were back in court.

This time, Will crushed John Harvey. A judge dismissed the elder brother's complaints and decided Will was entitled to all of the money John Harvey had made off of his cereal in the last ten years. John Harvey appealed to the Michigan Supreme Court, but they unanimously backed his brother.

Besting John Harvey so thoroughly did not make Will a better person. After a lifetime of feeling beaten down, Will became bitter, passive-aggressive, paranoid, and hostile. His marriages fell apart. Two of his sons broke off contact with him. After he died at the age of 91 years old, one of his grandsons described it as a relief.

"He got the ultimate revenge," Markel said, "but he couldn't enjoy it."

The brothers never fixed their shattered relationship. When they did meet, Will insisted upon having a third party in the room. Near the end of his life, John wrote Will an emotional letter— a mea culpa— from a man who was clearly full of regret.

But Will didn't get the letter. Because John Harvey's secretary never sent it to him.

"She didn't want it to be sent because it made John Harvey look weak," Markel said.

Will finally received the letter in 1948, years after John Harvey's death. By then, Will was blind from glaucoma.

"The letter had to be read to him," Markel said. "There were tears and silent stoicism…. it must have hurt him to the core."

Most people's names are not going to be remembered. Yet these two brothers from a tiny town in the middle of the state of Michigan are still being talked about.