The phone call that Ray Charles placed to Atlantic Records in early 1959 went something like this: “I’m playing a song out here on the road, and I don’t know what it is—it’s just a song I made up, but the people are just going wild every time we play it, and I think we ought to record it.” The song Ray Charles was referring to was “What’d I Say,” which went on to become one of the greatest rhythm-and-blues records ever made. Composed spontaneously out of sheer showbiz necessity, “What’d I Say” was laid down on tape on this day in 1959, at the Atlantic Records studios in New York City.

The necessity that drove Ray Charles to invent “What’d I Say” was simple: the need to fill time. Ten or 12 minutes before the end of a contractually required four-hour performance at a dance in Pittsburgh one night, Charles and his band ran completely out of songs to play. “So I began noodling—just a little riff that floated into my head,” Charles explained many years later. “One thing led to another and I found myself singing and wanting the girls to repeat after me….Then I could feel the whole room bouncing and shaking and carrying on something fierce.”

What was it about “What’d I Say” that so captivated the audience at the Pittsburgh dance that night and the rest of humanity ever since then? Charles always thought it was the sound of his Wurlitzer electric piano, a very unfamiliar instrument at the time. Others would say it was the call-and-response in the song’s bridge—all unnnhs and ooohs and other sounds not typically found on the average pop record of 1959. Whatever it was, it worked well enough to become Charles’ closing number from that night in Pittsburgh until his final show.

“You start ’em off, you get ’em just first tapping their feet. Next thing they got their hands goin’, and next thing they got their mouth open and they’re yelling, and they’re singin’ and they’re screamin’. It’s a great feeling when you got your audience involved with you.”