On March 18, 1911, composer Irving Berlin copyrights “Alexander’s Ragtime Band,” the multimillion-selling smash hit that helped turn American popular music into a major international phenomenon, both culturally and economically.

A century ago, even before the phonograph had become a common household item, there was already a burgeoning music industry in the United States based not on the sale of recorded musical performances, but on the sale of sheet music. It was in the medium of printed paper, and not grooved lacquer or vinyl discs, that songs gained popularity in the first two decades of the 20th century, and no song gained greater popularity in that era than Irving Berlin’s “Alexander’s Ragtime Band.”

It may seem like a rather grand claim to make about a simple, catchy tune, but then as now, simple and catchy were great virtues in the realm of pop music. Most people first encountered “Alexander’s Ragtime Band” when it was played on the piano by a friend or family member. This was the way that songs caught on in the era before radio, and part of what helped “Alexander” catch on was its relative lack of complexity.

Though nominally a ragtime tune, anyone who plays the piano would quickly recognize the differences between it and a true rag like Scott Joplin’s “The Entertainer,” which places some fairly significant demands on both the left and right hand. “Alexander’s Ragtime Band” is a vastly simpler piece for an amateur to master, and this greatly encouraged sheet music sales, which topped 1.5 million copies in the first 18 months after its publication.

Though it gained worldwide popularity purely as a piece of printed sheet music, innumerable recorded versions of “Alexander’s Ragtime Band” would soon follow, particularly after lyrics were added to what was originally an instrumental tune. Those lyrics—”Come on and hear, Come on and hear…”—and that tune are still familiar a century after they were written. Some of Irving Berlin’s later contributions to the American popular music canon—songs like “White Christmas,” “God Bless America” and “There’s No Business Like Show Business”—eclipsed even the massive success of “Alexander’s Ragtime Band.” It’s entirely possible, however, that those 20th-century classics would never have been written were it not for the commercial success that Irving Berlin achieved with the song he copyrighted on this day in 1911.