March Madness, the shorthand name for the NCAA Division I Men’s Basketball Tournament, is a phenomenon that raises an estimated $1 billion annually for the athletic association and its member teams.

But while “March Madness” is commonly used to refer to the college tournament, the origins of the term have been linked to an association that represents high school athletics.

In 1937, the phrase came to life as the name for the Indiana High School Athletic Association’s annual basketball tournament, according to a January 1937 Associated Press story that appeared in the Lafayette Journal & Courier.

“Holiday tournaments over, Indiana’s high school basketball teams this week settle into the home stretch before the annual ‘March madness’—the state tournament,” the AP article stated.

But neighboring Illinois can also stake an early claim to the term, as Time recently reported and NPR noted in 2015. According to those accounts, Henry V. Porter, the assistant executive secretary of the Illinois High School Association (IHSA), used the phrase in a March 1939 issue of Illinois High School Athlete. Although the Indiana source is dated two years earlier, Porter is commonly cited as having coined the phrase, and IHSA would later embrace it as its own.

According to a search of Newspapers.com, the term was heavily used in Indiana newspapers during the late 1930s, and the first mention of March Madness in relation to basketball in an Illinois newspaper was in a 1940 article, referring to the Indiana tournament.

Whoever was first, the term has deep association roots. IHSA used the annual event as a way to unify the state during World War II. Porter even wrote a poem about it in 1942. Here’s a passage:

The gym lights gleam like a beacon beam

And a million motors hum

In a good will flight on a Friday night;

For basketball beckons, “Come!”

A sharp-shooting mite is king tonight.

The Madness of March is running.

The winged feet fly, the ball sails high

And field goal hunters are gunning.

In 1989, IHSA trademarked the phrase and licensed it to other school tournaments around the country.

Meanwhile, the NCAA’s men’s basketball tournament got its start around the same time, in 1939. But it would be decades before it became the modern-day March Madness phenomeneon that captivates fans, distracts workers, and gets underway again this week.

An Indiana high school basketball game, circa 1915. (Indiana Historical Bureau)